Add plan format validator hook to detect malformed task labels

- Strengthen Prometheus plan template with FORMAT constraint
- Add task label format check to Oracle phase-2 (N/6 → N/7)
- Add format checks to self-review checklist
- New plan-format-validator hook: compares raw checkbox count
  against getPlanProgress() after plan writes, warns agent when
  labels are malformed (0/0 or partial skip scenarios)

src/hooks/index.ts

@@ -67,3 +67,4 @@ export { createWebFetchRedirectGuardHook } from "./webfetch-redirect-guard"
 export { createLegacyPluginToastHook } from "./legacy-plugin-toast"
 export { createFsyncSkipWarningHook } from "./fsync-skip-warning"
 export { createNotepadWriteGuardHook } from "./notepad-write-guard"
+export { createPlanFormatValidatorHook } from "./plan-format-validator"