merge: AgentProject membership — the junction is now load-bearing

Merges feat/agent-project-membership (task 166/152). An agent can finally join
many projects: membership routes, per-membership role and optional brain
override, chat resolving context from the membership, and CLI attach-agent /
detach-agent / get memberships. The legacy Agent.projectId fallback is kept for
this release as the schema comment promises.

Conflict resolved in main.ts: that branch added its RBAC case to
mapUrlToPermission inline, while this branch had extracted the function to
middleware/url-permission.ts so it could be tested. Kept the extraction and
ported the case into it — joining a team is `edit:agents:<name>`, not
`create:agents`, which is the authority to mint a whole agent.

Also fixes something the extraction makes possible. security.test.ts contained a
hand-copied reproduction of mapUrlToPermission, because main.ts self-invokes
main() and nothing in it was importable. A security test asserting against a
copy stops testing the system the moment the real one changes, and this copy had
already drifted. It now imports the real function; all 18 assertions still pass,
against the code that actually runs.

Local: build clean, workspace 2550 passed, lint unchanged at 794 errors.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N4wNHWf7xSwnZCWpJcyv9p

.taskmaster/tasks/task_157.md

@@ -0,0 +1,26 @@
+# Task ID: 157
+
+**Title:** Smoke test for task lifecycle transitions
+
+**Status:** pending
+
+**Dependencies:** 131, 149, 153
+
+**Priority:** medium
+
+**Description:** Create smoke test driving a task through full lifecycle including rejected accept-gate bounce
+
+**Details:**
+
+Create src/mcplocal/tests/smoke/task-lifecycle.smoke.test.ts:
+1. Create Epic → EpicTask → Task
+2. Transition task: todo → in_progress → building → self_testing → qa_review → done → awaiting_review
+3. Test reject: awaiting_review → in_progress
+4. Advance again to awaiting_review
+5. Test accept: verify merge called (may need mock git provider for smoke)
+6. Verify TaskEvents recorded for all transitions
+7. Follow smoke test patterns
+
+**Test Strategy:**
+
+Run against live mcpd. Verify each transition succeeds, events logged, reject bounces state correctly.