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_065.md

@@ -0,0 +1,63 @@
+# Task ID: 65
+
+**Title:** Add unit tests for gating state machine
+
+**Status:** done
+
+**Dependencies:** 50 ✓, 52 ✓
+
+**Priority:** high
+
+**Description:** Create comprehensive unit tests for the session gating state machine covering all transitions and edge cases.
+
+**Details:**
+
+1. Add tests in `/src/mcplocal/tests/router-gating.test.ts`:
+   ```typescript
+   describe('Gating State Machine', () => {
+     describe('initial state', () => {
+       it('starts gated for gated project', () => {
+         const router = createRouter({ gated: true });
+         const state = router.getSessionState('session1');
+         expect(state.gated).toBe(true);
+       });
+       
+       it('starts ungated for non-gated project', () => {
+         const router = createRouter({ gated: false });
+         const state = router.getSessionState('session1');
+         expect(state.gated).toBe(false);
+       });
+     });
+     
+     describe('begin_session transition', () => {
+       it('ungates session on successful begin_session', async () => {
+         const router = createGatedRouter();
+         await router.handleBeginSession('session1', { tags: ['test'] });
+         expect(router.getSessionState('session1').gated).toBe(false);
+       });
+       
+       it('returns matched prompts', async () => { ... });
+       it('sends notifications/tools/list_changed', async () => { ... });
+     });
+     
+     describe('intercept transition', () => {
+       it('ungates session on tool call intercept', async () => { ... });
+       it('extracts keywords from tool call', async () => { ... });
+       it('injects briefing with tool result', async () => { ... });
+     });
+     
+     describe('tools/list behavior', () => {
+       it('returns only begin_session while gated', async () => { ... });
+       it('returns all tools + read_prompts after ungating', async () => { ... });
+     });
+   });
+   ```
+
+**Test Strategy:**
+
+This task IS the test implementation. Verify:
+- Initial state tests pass
+- Transition tests cover happy paths
+- Edge case tests (already ungated, etc.)
+- Notification tests verify signals sent
+- Tests use proper mocking