feat(RMGR-WP-0001): complete T05 end-to-end vertical slice

Implement observe/reconcile/update-task-status CLI path: workplan parse,
JSON projection index, git-backed task status writeback with correlation
events, and E2E pytest plus evidence artifacts. Finish foundation workplan.

workplans/RMGR-WP-0001-foundation.md

@@ -4,7 +4,7 @@ type: workplan
 title: "Repo Manager architecture and foundation"
 domain: infotech
 repo: repo-manager
-status: active
+status: finished
 owner: codex
 topic_slug: repo-manager
 created: "2026-08-09"
@@ -104,7 +104,7 @@ skeleton. Package scaffold + version test landed (no business logic yet).
 
 ```task
 id: RMGR-WP-0001-T05
-status: todo
+status: done
 priority: high
 state_hub_task_id: "5036a248-1c47-423f-be8d-4fd232896c31"
 ```
@@ -114,6 +114,13 @@ work, emit a normalized change through hub-core contracts, apply one authorized
 file-backed transition, and prove the resulting Git evidence and rebuilt
 projection.
 
+**Result (2026-08-09):** Vertical slice implemented — `rmgr observe|reconcile|
+update-task-status`. Parser, JSON projection (`.repo-manager/index.json`),
+git-backed writeback with required `evidence.git_sha`, contract-shaped events.
+Proof: `pytest tests/test_e2e_vertical_slice.py` + `docs/evidence/t05-*`.
+Limits: local JSON index (not Postgres yet); hub-core HTTP emit deferred;
+authz not enforced on CLI.
+
 ## Acceptance
 
 - [x] The authority and data model are explicit.
@@ -121,4 +128,4 @@ projection.
   - (semantics + catalog done; automated suite with runtime in T04/T05)
 - [x] State Hub extraction candidates have dispositions.
 - [x] The implementation foundation has a recorded decision.
-- [ ] One repository completes the end-to-end vertical slice.
+- [x] One repository completes the end-to-end vertical slice.