feat: add State Hub bulk status skill

workplans/STATE-WP-0058-agent-skill-hub-interaction.md

@@ -4,7 +4,7 @@ type: workplan
 title: "State Hub Agent Skill — front-load tool schemas + batched writes"
 domain: custodian
 repo: state-hub
-status: ready
+status: finished
 owner: codex
 topic_slug: custodian
 created: "2026-06-07"
@@ -37,7 +37,7 @@ of sessions).
 
 ```task
 id: STATE-WP-0058-T01
-status: todo
+status: done
 priority: high
 state_hub_task_id: "6f211ccc-e505-419d-90cc-25874ba98f39"
 ```
@@ -54,7 +54,7 @@ model). Directly targets the `ToolSearch`-thrash finding.
 
 ```task
 id: STATE-WP-0058-T02
-status: todo
+status: done
 priority: high
 state_hub_task_id: "2138505a-ea49-4ccc-9dec-a176badaa7a5"
 ```
@@ -69,7 +69,7 @@ preserve the automatic `progress_event` semantics on each write.
 
 ```task
 id: STATE-WP-0058-T03
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "cf8d41f8-7831-4c1b-9dfa-58660174294b"
 ```
@@ -83,3 +83,27 @@ workplan updates, notify the operator to run from `~/state-hub`:
 ```bash
 make fix-consistency REPO=state-hub
 ```
+
+## Verification Notes
+
+Completed 2026-06-07:
+
+- Added `skills/state-hub/SKILL.md` plus
+  `skills/state-hub/references/tool-signatures.md` to front-load the
+  high-frequency State Hub MCP signatures, session flow, ADR-001 files-first
+  boundary, REST fallbacks, and batched-write guidance.
+- Added `POST /tasks/bulk-status-sync` for checkpoint task-status batching.
+  The endpoint updates all requested task statuses in one transaction, rejects
+  duplicate task ids with `400`, rejects missing task ids with `404`, and emits
+  one `task_status_changed` progress event per successful item.
+- Added MCP wrapper `bulk_update_task_statuses(updates, author?, session_id?)`
+  and documented it in `mcp_server/TOOLS.md`.
+- Sent completion/signature handoff to `helix_forge` as message
+  `7236bd1c-b60d-481a-bc05-3080c4b46f72`, followed by tracked-path
+  correction `1a322eed-96d6-45d4-9e0a-685a6f66e180`.
+
+Verification:
+
+- `.venv/bin/python -m pytest tests/test_task_bulk_status_sync.py tests/test_mcp_write_tools.py -q` -> 12 passed
+- `.venv/bin/python -m pytest tests/test_task_bulk_status_sync.py tests/test_mcp_write_tools.py tests/test_mcp_smoke.py -q` -> 25 passed
+- `git diff --check` -> clean