docs(zddc-server): normalize .zddc YAML examples to block-style lists

Block style (one '- entry' per line) is recommended for hand-edited config
in this repo: cleaner diffs, easier to comment per-entry, no surprise YAML
quoting traps. The Admin Debug Page example mixed admins (block) with
acl.allow (flow); flip allow to block too for consistency.

Inline-in-table flow-style examples (lines 143-145) stay flow — block
style would mangle the cell layout — and that's a fine exception when the
list lives inside a one-cell context.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

zddc/README.md

@@ -202,7 +202,8 @@ admins:
   - alice@mycompany.com
   - "*@admin.mycompany.com"
 acl:
-  allow: ["*@mycompany.com"]
+  allow:
+    - "*@mycompany.com"
 ```
 
 Only the root-level `admins` entry is honored — subdirectory `.zddc` files'