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_148.md

@@ -0,0 +1,27 @@
+# Task ID: 148
+
+**Title:** GitProvider interface and Gitea driver
+
+**Status:** pending
+
+**Dependencies:** 132
+
+**Priority:** high
+
+**Description:** Create GitProvider interface and Gitea implementation for PR creation, status check, and merge
+
+**Details:**
+
+Create src/mcpd/src/services/git-provider.ts and src/mcpd/src/services/git-provider/gitea.ts:
+1. GitProvider interface: createPullRequest(repo, branch, title, body), getPullRequest(repo, prNumber), getCombinedStatus(repo, ref), mergePullRequest(repo, prNumber, method?)
+2. Gitea driver: implement using Gitea API v1
+   - POST /api/v1/repos/:owner/:repo/pulls for createPullRequest
+   - GET /api/v1/repos/:owner/:repo/pulls/:id for getPullRequest
+   - GET /api/v1/repos/:owner/:repo/commits/:sha/status for getCombinedStatus
+   - POST /api/v1/repos/:owner/:repo/pulls/:id/merge for mergePullRequest
+3. Credentials resolved from CodeRepo's Secret via SecretService
+4. Reference pr.sh script for endpoint shapes
+
+**Test Strategy:**
+
+Unit tests with mocked HTTP: test each method sends correct request, handles success/error responses. Integration test against local Gitea instance if available.