feat(tasks): adopt canonical task statuses

scripts/project_rules/agents-codex.template

@@ -63,8 +63,8 @@ Omit `workstream_id` / `task_id` when not applicable.
 ```bash
 curl -s -X PATCH "http://127.0.0.1:8000/tasks/<task_id>" \
   -H "Content-Type: application/json" \
-  -d '{"status": "in_progress"}'
-# values: todo | in_progress | done | blocked
+  -d '{"status": "progress"}'
+# values: wait | todo | progress | done | cancel
 ```
 
 ### Flag a task for human review
@@ -83,7 +83,7 @@ curl -s -X PATCH "http://127.0.0.1:8000/tasks/<task_id>" \
 1. `cat .custodian-brief.md` — domain goal and open workstreams (offline-safe)
 2. Check inbox: `GET /messages/?to_agent={REPO_SLUG}&unread_only=true`; mark read
 3. Scan workplans: `ls workplans/` — note `status: ready`, `active`, or `blocked` files and open tasks
-4. Check blocked tasks: `GET /tasks/?needs_human=true`
+4. Check human-needed tasks: `GET /tasks/?needs_human=true`
 
 **During work:**
 - Update task statuses in workplan files as tasks progress
@@ -146,7 +146,7 @@ derived health labels, not frontmatter statuses.
 
 ` ` `task
 id: {WP_PREFIX}-NNNN-T01
-status: todo | in_progress | done | blocked
+status: wait | todo | progress | done | cancel
 priority: high | medium | low
 state_hub_task_id: "<uuid>"         # written by fix-consistency — do not edit
 ` ` `
@@ -154,7 +154,7 @@ state_hub_task_id: "<uuid>"         # written by fix-consistency — do not edit
 Task description text.
 ```
 
-Status progression: `todo` → `in_progress` → `done` (or `blocked`)
+Status progression: `todo` → `progress` → `done`; use `wait` for waiting/blocked work and `cancel` for stopped work.
 
 To create a new workplan:
 1. Write the file following the format above