docs: add UUID naming rule to AGENTS.md + DOCS_STANDARD.md — never bare uuid, always file_uuid/identity_uuid

AGENTS.md

@@ -673,6 +673,20 @@ docs_v1.0/M4_workspace/YYYY-MM-DD_<topic>_test_report.md (測試報告)
 
 詳細規範見 `docs_v1.0/M4_workspace/M4_NOTIFICATION_PROTOCOL.md`。
 
+## UUID Naming Rule
+
+**Never use bare `uuid` in API route paths, query params, JSON keys, or code variable names. Always qualify:**
+
+| Context | Must use | Never |
+|---------|----------|-------|
+| Video/file resource | `file_uuid` | `uuid` |
+| Identity resource | `identity_uuid` | `uuid` |
+| Query parameter | `file_uuid=`, `identity_uuid=` | `uuid=` |
+| Route path | `:file_uuid`, `:identity_uuid` | `:uuid` |
+| JSON key | `"file_uuid"`, `"identity_uuid"` | `"uuid"` |
+
+This applies to docs, code, API responses, and curl examples. Exceptions: internal database primary key names (e.g. `identities.uuid` column).
+
 ## Document Compliance Checklist
 
 Before creating any `REFERENCE/*.md` file, verify all items below.
@@ -689,6 +703,13 @@ Before creating any `REFERENCE/*.md` file, verify all items below.
 | 6 | English content | Entire file in English |
 | 7 | REFERENCE/ path | File must reside under `docs_v1.0/REFERENCE/` |
 
+### P0b — UUID Naming
+
+| # | Check | Rule |
+|---|-------|------|
+| 8 | `file_uuid` not bare `uuid` | All file references use `file_uuid` (see UUID Naming Rule above) |
+| 9 | `identity_uuid` not bare `uuid` | All identity references use `identity_uuid` |
+
 ### P1 — Suggested (3 items)
 
 | # | Check | Note |