# AGENTS.md — ZDDC

## Commands

```bash
# Dev build: 5 HTML tools + cross-compile zddc-server binaries + regen the
# matrix at website/releases/index.html. dist/ artifacts only — no
# website/releases/ side-effect for the build outputs themselves.
sh build.sh

# Build a single HTML tool (archive | transmittal | classifier | mdedit | landing)
sh tool/build.sh

# ── Lockstep release: bumps ALL six tools (5 HTML + zddc-server) at once ──
#
# Coordinated version is max(latest tag across all six) + 1, so they
# always converge. Channel cuts (alpha/beta) follow the same lockstep —
# every tool's channel mirror is overwritten together. Workflow:
#   alpha = active dev iteration  →  beta = ready for general testing  →  stable = ship
sh build.sh --release            # stable, auto-coordinated next version
sh build.sh --release 1.2.0      # stable, explicit version
sh build.sh --release alpha      # alpha cut for everything
sh build.sh --release beta       # beta cut for everything (cascades alpha → beta)

# Single-tool release (rare; prefer the lockstep top-level cut above so
# versions don't drift between tools). Same flags as the top-level form.
sh tool/build.sh --release [<version>|alpha|beta]
./freshen-channel <tool> <channel>      # rebuild one tool's alpha/beta from its current stable tag

# Test all tools
npm test

# Test single tool
npx playwright test tool        # archive | transmittal | classifier | mdedit

# Dev server (cache-busting HTTP, on port 8000)
./dev-server start
./dev-server stop
```

No lint, typecheck, or format commands exist — the project is plain sh + vanilla JS.

The build ends with a **channel-link verifier** that asserts every
`<tool>_{stable,beta,alpha}.html` (and zddc-server's per-platform binary
mirrors + stub pages) resolves. Build fails if any link is dangling.
Bootstrap-friendly: zddc-server checks are skipped until the first
`--release` cut materializes the binaries under `website/releases/`.

## Architecture

Five independent single-file HTML tools (`archive`, `transmittal`, `classifier`, `mdedit`, `landing`). Each compiles to one self-contained `.html` in `dist/` with all CSS and JS inlined — the first four name their output `dist/tool.html`; `landing` writes `dist/index.html` (it's served at `/` by `zddc-server`). Tools share a small set of canonical helpers in `shared/` (filename parsing, ZDDC filter UI, theme, help) — see "Shared modules" below.

```
tool/
  css/           source stylesheets (concatenated in order)
  js/            vanilla JS IIFEs (concatenated in order)
  template.html  placeholder markers: {{CSS_PLACEHOLDER}}, {{JS_PLACEHOLDER}}, {{BUILD_LABEL}}
  build.sh       assembles dist/tool.html
  dist/tool.html generated output — committed with `git add -f`

shared/
  base.css        CSS tokens and primitives included first by every tool's CSS build
  zddc.js         canonical filename/folder/revision parsers, formatters, status validation
  zddc-filter.js  shared ZDDC project/status filter UI module
  theme.js        light/dark theme switcher
  help.js         shared help dialog module
  build-lib.sh    POSIX sh helpers (ensure_exists, concat_files, build_timestamp)
                  sourced by every tool's build.sh via: . "$root_dir/../shared/build-lib.sh"

website/
  index.html                          hand-edited intro page + install snippets (root URL)
  releases/
    index.html                        versions index, regenerated by build.sh from filesystem scan
    <tool>_v<X.Y.Z>.html              real per-version files (committed, immutable)
    <tool>_v<X.Y>.html  -> ...        symlink: latest patch within X.Y.*
    <tool>_v<X>.html    -> ...        symlink: latest within X.*.*
    <tool>_stable.html  -> ...        symlink: current stable
    <tool>_beta.html    -> ...        symlink to stable (or real bytes if active beta)
    <tool>_alpha.html   -> ...        symlink to beta/stable (or real bytes if active alpha)

helm/
  zddc-server-prod/  production-shaped Helm chart (compiles from source via init container)
  zddc-server-dev/   dev-shaped variant (tracks main HEAD; debug-level logging; faster probes)
  README.md          chart design rationale + quick-start
```

**Critical:** `dist/` files are gitignored. They're the canonical built artifact for testing and the source for `--release` writes into `website/releases/`, but they aren't checked in. Never edit them directly.

`website/releases/` IS committed — per-version HTML and per-version zddc-server binaries as real bytes, partial-version pins (`_v<X.Y>`, `_v<X>`) and channel mirrors (`_stable`, `_beta`, `_alpha`) as symlinks. `shared/build-lib.sh` provides `promote_release` (HTML tools) and `promote_zddc_server` (binaries + matching stub pages); the top-level `build.sh --release` calls them in lockstep. zddc-server binaries live in this repo too — there's no Codeberg release-asset publication anymore; everything serves from `zddc.varasys.io/releases/`.

## Shared CSS (`shared/base.css`)

Included as the **first** positional arg to every tool's `concat_files` CSS call. Provides:
- `:root` CSS custom properties — `--primary`, `--bg`, `--text`, `--border`, `--font`, etc.
- Brand color: `--primary: #2a5a8a` (matches zddc.varasys.io)
- Button primitive: `.btn`, `.btn-primary`, `.btn-secondary`, `.btn-sm`, `.btn-lg`, `.btn-link`
- `.app-header` + `.app-header__title` chrome rules
- `.build-timestamp`, `.hidden`, `.truncate`, webkit scrollbars

**Do not** define these in any tool's own CSS — they come from shared.

**Toast CSS** lives in `classifier/css/base.css` only (classifier is the only tool that uses toasts).

## Transmittal CSS quirks

- `transmittal/css/base.css` overrides `html { font-size: 16px }` inside `@media screen` — this must stay. `shared/base.css` sets `14px`; transmittal's floating labels are rem-based and were designed for 16px.
- The floating label position is defined in `transmittal/css/forms.css`, not Tailwind classes. If adding new Tailwind classes to `template.html`, add them to `transmittal/css/utilities.css` too — there is no Tailwind build step.

## Build system rules

- Every `build.sh` sources `shared/build-lib.sh` first (provides `ensure_exists`, `concat_files`, `build_timestamp`). Set `root_dir` before sourcing.
- Build scripts use **POSIX sh** (`#!/bin/sh` with `set -eu`), not bash.
- `concat_files` accepts **positional args only** (not array names).
- `awk` processes `template.html`, replacing `{{PLACEHOLDER}}` markers and stripping CDN `<script>`/`<link>` tags (pattern: `https?://`)
- `{{BUILD_LABEL}}` is substituted in all five tools via `gsub` in awk (use `gsub`, not `print` — the placeholder is inline in an HTML line). Value is `Built: <timestamp> BETA` for dev builds, `v<version>` for stable releases, and `<channel> · <date> · <sha>` for alpha/beta channel builds; computed before the awk step. The shared `is_red` flag controls whether the label is wrapped in a red+bold `<span>` (true for dev/alpha/beta, false for stable).
- Cleans up temp files via `trap cleanup EXIT`

**`</` escaping is mandatory.** Any JS containing `</tag>` inside string or template literals will break inline `<script>` embedding. Run:
```bash
sed 's#</#<\\/#g' "$input_js" > "$safe_js"
```
Required for any new tool with vendor JS or JS containing HTML template literals.

## JS module pattern

All JS is vanilla, no bundlers. Files are IIFEs, registered on `window.app.modules`. Load order = declaration order in `build.sh`. `window.app` is the only global.

```javascript
(function() {
    window.app.modules.mymodule = { ... };
})();
```

**Exception:** archive uses plain globals (`APP_STATE`, top-level functions) — not the IIFE/modules pattern.

## ZDDC filename parsers

All parsing/formatting goes through `shared/zddc.js`, exposed as `window.zddc`. Tools call it directly — no per-tool wrappers.

`window.zddc` exports:
- `parseFilename(name)` → `{ trackingNumber, revision, status, title, extension, valid } | null` (extension WITHOUT leading dot)
- `parseFolder(name)` → `{ date, trackingNumber, status, title, valid } | null`
- `parseRevision(rev)` → `{ base, modifier, modifierType, modifierNumber, isDraft, modifierIsDraft, full }`
- `compareRevisions(a, b)` → number (canonical sort order)
- `formatFilename(parts)` / `formatFolder(parts)` — round-trips parsed output
- `isValidStatus(code)` — accepts known status codes plus `---`

All file objects across tools use `file.trackingNumber` (string) and `file.extension` (string, **no leading dot**, e.g. `'pdf'` not `'.pdf'`). When concatenating into a filename, write `name + '.' + ext`.

Coverage lives in `tests/zddc.spec.js` (47 cases). Add new edge cases there, not in tool tests.

## Testing quirks

- Playwright + Chromium only (File System Access API requirement)
- Tests open `dist/tool.html` via `file://` protocol — **always build before testing**
- File System Access API is mocked via `page.addInitScript()` using `tests/fixtures/mock-fs-api.js`
- Use `waitUntil: 'load'` or `'domcontentloaded'` not `'networkidle'` — bundled scripts keep the network "active"
- Archive's `#noDirectoryMessage` empty-state overlay is `position: absolute; top: 50px` — it must clear the header or it will block button clicks in tests

## ZDDC filename convention

Format: `trackingNumber_revision (status) - title.extension`

- `trackingNumber`: no spaces or underscores (e.g. `123456-EL-SPC-2623`)
- `revision`: `A`, `B`, `0`; draft prefix `~`; modifiers `+C1`, `+B1`, `+N1`, `+Q1`
- `status`: `IFA IFB IFC IFD IFI IFP IFR IFU REC RSA RSB RSC RSD RSI` or `---`
- Folder names prefix with date: `2025-10-31_trackingNumber (status) - title`

## Git workflow

- Feature-branch workflow; squash-merge feature branches to `main`
- Conventional commits: `feat(archive): ...`, `fix(transmittal): ...`
- Release tags: `<tool>-v<X.Y.Z>` per tool, all six sharing the same X.Y.Z on a coordinated cut (e.g. `archive-v0.0.8`, `transmittal-v0.0.8`, `classifier-v0.0.8`, `mdedit-v0.0.8`, `landing-v0.0.8`, `zddc-server-v0.0.8`)
- Commit dist files: `git add -f tool/dist/tool.html`
- Commit zddc-server binaries (per-version + symlinks): they live under `website/releases/` like every other release artifact

### Releasing — lockstep, channels, layout

**Lockstep convention.** Every release cut bumps all six artifacts (5 HTML tools + zddc-server) to the same version, even if a tool didn't change. Per-tool independent versions are gone. The coordinated next-stable target is `max(latest tag across all six tools) + 1` — `_coordinated_next_stable` in `shared/build-lib.sh`. Channel cuts (alpha/beta) follow the same lockstep — every tool's channel mirror is overwritten in step. Three channels, ordered: **alpha** (dev iteration) → **beta** (general testing) → **stable** (ship).

**Storage model.** All release artifacts live under `website/releases/` and are served from `zddc.varasys.io/releases/`. No Codeberg release assets, no third-party mirrors.

| Artifact | Type | Layout |
|---|---|---|
| `<tool>_v<X.Y.Z>.html` | real, immutable | per-version HTML for each of archive, transmittal, classifier, mdedit, landing |
| `<tool>_v<X.Y>.html`, `<tool>_v<X>.html` | symlinks | partial-version pins |
| `<tool>_<channel>.html` | symlink (or real bytes during active channel dev) | mutable channel mirror per tool, channel ∈ {stable, beta, alpha} |
| `zddc-server_v<X.Y.Z>_<platform>` | real binary | per-version cross-compiled binary, platform ∈ {linux-amd64, darwin-amd64, darwin-arm64, windows-amd64.exe} |
| `zddc-server_v<X.Y>_<platform>`, `zddc-server_v<X>_<platform>`, `zddc-server_<channel>_<platform>` | symlinks (or real bytes during active channel dev) | partial-pin and channel mirrors per platform — same cascade as the HTML tools |
| `zddc-server_<X>.html` | generated stub page | per-version / per-channel; lists the four platform downloads. This is what the matrix-cell link points at — one stub fans out to four binaries |
| `index.html` | regenerated by `build.sh` | matrix table, one column per tool, one row per release |

**Single point of truth.** `sh build.sh --release` is the canonical lockstep cut. It forwards each HTML tool's build with the agreed version, then `promote_zddc_server` (in `shared/build-lib.sh`) copies the freshly cross-compiled binaries into `website/releases/` with the matching symlink chain, then `write_zddc_server_stubs_all` regenerates every stub page, then `build_releases_index` rewrites the matrix, then `verify_channel_links` asserts nothing dangles.

- **Stable** (`sh build.sh --release` or `--release X.Y.Z`): Writes per-version HTML for the five HTML tools + per-version binaries for zddc-server (real bytes, immutable). Refreshes 5 symlinks per HTML tool + 5 symlinks per zddc-server platform → the new version. Tags all six: `<tool>-v<X.Y.Z>`. Cascade: stable cut means beta and alpha both reset to stable for every tool. Skips silently if source for an HTML tool hasn't changed since the latest stable tag (the binary always builds).
- **Beta** (`sh build.sh --release beta`): Overwrites `<tool>_beta.html` with dist bytes for each HTML tool, and `zddc-server_beta_<platform>` with each platform's binary. Cascade: `<tool>_alpha.html` → `<tool>_beta.html` and `zddc-server_alpha_<platform>` → `zddc-server_beta_<platform>` (symlinks). No tag.
- **Alpha** (`sh build.sh --release alpha`): Overwrites only the alpha mirrors, all six tools. No tag, no other side-effects.
- **Plain dev builds** (no `--release`): produce `tool/dist/<tool>.html` for HTML tools and `zddc/dist/zddc-server-<platform>` binaries; do NOT touch `website/releases/`. The matrix index and stub pages still get regenerated from whatever `website/releases/` contains, so the build is idempotent for repeated dev runs.

On-page `{{BUILD_LABEL}}` format (HTML tools only — zddc-server's version comes from the binary itself):

- Plain dev: `vX.Y.Z-alpha · <full-ts> · <sha>[-dirty]` (red), where X.Y.Z is the per-tool next-stable target.
- `--release alpha`: `vX.Y.Z-alpha · <date> · <sha>` (red).
- `--release beta`: `vX.Y.Z-beta · <date> · <sha>` (red).
- `--release [version]`: `v<X.Y.Z>` (black).

After cutting a stable release, `git push origin main && git push origin --tags` to publish the new version files + symlinks + every per-tool tag in lockstep.

### Channel discipline (MUST rules)

The build enforces lockstep mechanically (one command bumps all six). The rules below are still on you.

1. **Stable doesn't regress.** No known-broken features that worked in the previous stable. If `v0.0.5` ships with a bug, the path forward is `v0.0.6` with a fix — never edit a previously-published per-version file in place. Stable per-version files are immutable.
2. **Lockstep is the contract.** Don't cut a single tool's release without bumping the rest. The HTML tool's standalone `--release` flag still exists as an escape hatch but emits a tag that immediately drifts out of sync with the others.
3. **No backports.** Always cut a new stable at a higher version. Users pinned to an old version stay pinned by choice.
4. **Alpha and beta are mutable.** Document this anywhere you invite users to test them. Pinning a deployment to a channel mirror means it gets rebuilt without notice. For reproducibility, pin to a per-version URL — `<tool>_v0.0.5.html` or `zddc-server_v0.0.5.html`.
5. **Cascade is automatic.** Stable cut → beta + alpha mirrors reset to stable (per-tool HTML AND per-platform zddc-server). Beta cut → alpha → beta. "No active beta" silently shows current stable. No freshen step required after a stable release.
6. **Hotfix path.** For critical bugs: fix on `main`, cut a new stable. Tag the commit message `fix:` or include "hotfix" so intent is visible in `git log`.
7. **Beta soak before promoting (recommended).** Give a beta a few days of exposure before cutting the same code as stable. Not enforced; use judgment for trivial changes.

### Freshen helper

`./freshen-channel <tool> <channel>` rebuilds the alpha or beta channel of a tool from its current stable tag — useful when you want a channel to advance to current stable code without doing active dev on it (e.g. after upstream dependency changes). Most of the time you don't need it: the cascade rule (rule 5 above) means a stable cut already resets the downstream channel symlinks. Use this when you specifically want a fresh build with a new on-page label timestamp instead of a symlink.

```sh
./freshen-channel archive alpha
./freshen-channel transmittal beta
```

What it does:

1. Finds the latest `<tool>-v*` clean stable tag.
2. Creates a temporary git worktree at that tag — does **not** touch the main worktree's HEAD or working tree.
3. Runs `<tool>/build.sh --release <channel>` inside the worktree, which overwrites `<tool>_<channel>.html` with the freshly-built bytes. (Note: this is in the worktree, not on main — you'll need to commit the resulting changes back to main afterward.)
4. Removes the worktree.

The build pipeline used is the one **at the tag**, not on `main`. That is intentional (pure reproducibility). If you have made build-system improvements since stable was cut and want the freshen to use them, cut a new stable first.

### Install model

No install script. Two paths:

- **Local** — download a tool `.html` from `https://zddc.varasys.io/releases/` and open it. Done.
- **Server** (`zddc-server`) — every tool is `//go:embed`'d into the binary at compile time (the current-stable build). The server virtually serves them at folder-name-driven paths:
  - `archive.html` at every directory (multi-project, project, archive, vendor levels)
  - `classifier.html` in any `Incoming`/`Working`/`Staging` directory and its subtree
  - `mdedit.html` in any `Working` directory and its subtree
  - `transmittal.html` in any `Staging` directory and its subtree
  - `index.html` (landing) only at the deployment root

  See `internal/apps/availability.go`. Outside these locations, requesting `<app>.html` returns 404 (just like any other missing file).

To override at any level, either:
1. Drop a real `<app>.html` file at the path → static handler serves it (highest priority).
2. Write an `apps:` entry in any `.zddc` along the path. Spec is one of `stable`/`beta`/`alpha`/`v0.0.4`/`v0.0`/`v0`/full URL/local path. Closer-to-leaf entries win.

URL sources fetch once and cache forever in `<ZDDC_ROOT>/_app/<host>/<path>`. To force a re-fetch, delete the cache file. No background refresh, no SHA-256 verification, no admin UI. If a configured URL fetch fails, the server falls back to the embedded copy and emits a one-time WARN log.

Operators audit by reading the `X-ZDDC-Source` response header: `fetch:URL` / `cache:URL` / `path:/abs` / `embedded:<app>@<build>`. Direct URL access to `/_app/...` is blocked at the dispatch layer.

**Runtime mode detection** in archive is independent of install: it auto-detects multi-project / project-root / in-archive from `?projects=` plus folder shape. The other tools don't care where they live.

### Worktrees

Use `git worktree` to run multiple agents on separate branches simultaneously without filesystem collisions.

- Worktrees live at `~/src/zddc-<branch-name>` (sibling of the main clone)
- Before starting work on a feature branch, check `git worktree list`; if no worktree exists, create one: `git worktree add ~/src/zddc-<branch-name> -b <branch-name>`
- All edits, builds (`sh build.sh`), and tests (`npm test`) run from within the worktree directory — build scripts use relative paths so this works correctly
- The `dist/` force-commit rule (`git add -f`) applies per-worktree
- After the branch is merged, clean up: `git worktree remove ~/src/zddc-<branch-name>` then delete the branch
- Never run `git checkout` or `git switch` inside a worktree that another agent may be using

## Transmittal-specific

- Two-phase hydration: `populateStatic()` before publish, `hydrate()` on load of published file
- Reactive state via Proxy — `app.state.mode = 'view'` auto-notifies subscribers
- Runtime CDN loads (jszip, docx-preview, xlsx) are allowed only for the optional DOCX/XLSX preview; core features work offline
- Published payload stored in `<script id="transmittal-data" type="application/json">`

## mdedit-specific

- `css/tailwind-utils.css` is a pre-generated static subset (~80 classes). Add new Tailwind classes here; do not re-run Tailwind.
- Toast UI Editor v3.2.2 is bundled in `vendor/`; `template.html` loads it from CDN for dev convenience
- `</` escaping is essential: `sed 's#</#<\\/#g'` runs on both app JS and vendor JS at build time

## zddc-server

Go HTTP server sub-project living at `zddc/`. Replaces `caddy file-server --browse` for ZDDC archives.

### Build

zddc-server ships as a cross-compiled binary, not a container image. There's no Containerfile or compose file in this repo (the chart Dockerfiles compile from source at deploy time at the right tag).

```sh
# Compile a local binary for the host platform (requires Go 1.24+)
(cd zddc && go build -o zddc-server ./cmd/zddc-server)

# Or run directly without producing a binary
(cd zddc && go run ./cmd/zddc-server)
```

The repo's top-level `sh build.sh` cross-compiles the four release binaries (linux/amd64, darwin/amd64, darwin/arm64, windows/amd64) into `zddc/dist/` via a containerized Go toolchain (podman or docker). On `--release` it also promotes those binaries to `website/releases/` with the matching symlink chain and stub pages — same lockstep flow as the HTML tools.

### Run (development)

```sh
ZDDC_ROOT=/path/to/your/archive ZDDC_TLS_CERT=none ZDDC_ADDR=:8080 \
  go run ./cmd/zddc-server
```

For a release binary downloaded from `zddc.varasys.io/releases/`:

```sh
curl -O https://zddc.varasys.io/releases/zddc-server_stable_linux-amd64
chmod +x zddc-server_stable_linux-amd64
ZDDC_ROOT=/path/to/your/archive ZDDC_TLS_CERT=none ZDDC_ADDR=:8080 \
  ./zddc-server_stable_linux-amd64
```

### Key environment variables

| Variable | Default | Purpose |
|---|---|---|
| `ZDDC_ROOT` | *(required)* | Path to served file tree |
| `ZDDC_ADDR` | `:8443` | Bind address |
| `ZDDC_EMAIL_HEADER` | `X-Auth-Request-Email` | Header set by upstream proxy with user email (oauth2-proxy / nginx auth-request convention) |
| `ZDDC_INDEX_PATH` | `.archive` | Virtual archive index URL segment |
| `ZDDC_LOG_LEVEL` | `info` | Logging verbosity |
| `ZDDC_CORS_ORIGIN` | `https://zddc.varasys.io` | Comma-separated CORS allowlist; empty value disables CORS. Default lets tools served from zddc.varasys.io call back into a customer-deployed server. |

### Release tagging

zddc-server has no separate release script anymore. The top-level `sh build.sh --release [version|alpha|beta]` is the canonical path: it cross-compiles the binaries inside the containerized Go toolchain, copies them into `website/releases/` with the lockstep symlink chain (one set of symlinks per platform), regenerates the per-version + per-channel stub pages, refreshes the matrix, and tags `zddc-server-v<X.Y.Z>` alongside the five HTML-tool tags.

```sh
sh build.sh --release            # lockstep stable, coordinated next version
sh build.sh --release 1.2.0      # lockstep stable, explicit version
sh build.sh --release alpha      # lockstep alpha cut for everything
sh build.sh --release beta       # lockstep beta cut for everything
```

The script tags every tool but does NOT push — finish with `git push origin main && git push origin --tags`.

**Versioning** — clean semver. Stable cuts emit one `<tool>-vX.Y.Z` tag per tool, all six sharing the same X.Y.Z. No `-alpha.N` / `-beta.N` counter tags — channel URLs are stable URLs by design. Historical per-tool independent tags (`archive-v0.0.2`, `zddc-server-v0.0.7`, etc.) stay as artifacts; the next coordinated cut jumps every tool to the same number.

**Binary distribution** — `website/releases/zddc-server_<X>_<platform>` are real static files served from `zddc.varasys.io/releases/`. No Codeberg release assets, no `$CODEBERG_TOKEN`, no third-party mirror. The matrix-cell link points at `zddc-server_<X>.html`, a generated stub page that surfaces the four platform downloads in one click.

There is no CI for this — solo workflow benefits from one canonical
local path that fails loudly and visibly on the developer's terminal.

### Notes

- No external test framework yet — Go unit tests run with `go test ./...` inside `zddc/` (requires Go 1.24+)
- Portfolio files (`*.portfolio`) in the served tree appear as virtual group directories
- Every folder under a project exposes a `.archive` virtual directory backed by that **project's** index bucket — the project is the first slash-separated segment of the contextPath. Depth within a project doesn't change scope: `/ProjectA/sub/sub/.archive/X.html` resolves the same as `/ProjectA/.archive/X.html`, just with a different URL prefix on the listing entries. The flat listing emits two redirect entries per tracking number: `<tracking>.html` (highest base rev) and `<tracking>_<rev>.html` (each specific base rev). Both redirect to the first chronologically received copy within that project. Modifier files (`<tracking>_<rev>+C1.html` etc.) remain reachable via the resolver but are not surfaced in the listing — they're return traffic, not primary documents. `/.archive/` at the very root has no project segment and returns 404 — stable references must include the project directory. Within one project, two different files claiming the same `(tracking, rev)` are an authoring mistake; chronological winner still wins, but a `WARN` is emitted with both paths. ACL is enforced twice: the listing endpoint is gated by the contextPath's `.zddc` chain, and each entry is then filtered against the ACL of its resolved file's directory — per-target denials return 404 rather than 403 to avoid leaking that the tracking number exists in another subtree.
- ACL is enforced via cascading `.zddc` YAML files; authentication is delegated to the upstream proxy via the `X-Auth-Request-Email` header (configurable with `ZDDC_EMAIL_HEADER`)
- `.zddc` schema also supports a top-level `admins:` glob list, peer to `acl.allow`/`acl.deny`. Honored **only** at the root `.zddc` (subdir `admins` entries are ignored to prevent privilege escalation via subtree write access). Drives the built-in debug dashboard at `/.admin/` (sub-routes: `/whoami`, `/config`, `/logs`); non-admin requests get 404 so the page is invisible. See `zddc/README.md` § "Admin Debug Page".
- `GET /.auth/admin` is a **forward_auth target** for upstream proxies — returns 200 if the request's `X-Auth-Request-Email` is in the root `.zddc` `admins:` list, 403 otherwise. No body, no UI. Used by the dev-shell pod's Caddy to gate `/devshell/*` (code-server) on root-admin status without code-server learning about auth. zddc-server's own routes use the regular `.zddc` cascade ACL — they do NOT go through this endpoint.
- **Reserved entry prefixes** under `ZDDC_ROOT`: `.`-prefixed entries are excluded from listings AND 404 on direct fetch (only `.archive` and `.admin` are exempt) — for invisible side-state like dev-shell home dirs. `_`-prefixed entries are excluded from listings only — for operator scaffolding like the `_template/` directory created by the self-contained install snippet, still reachable by direct URL. Drop side-state under `_` if it should be linkable; under `.` if it should be unreachable.