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_150.md

@@ -0,0 +1,28 @@
+# Task ID: 150
+
+**Title:** QA/Security/SRE stage verdicts
+
+**Status:** pending
+
+**Dependencies:** 130
+
+**Priority:** medium
+
+**Description:** Implement risk-scaled verification stages that record commit-pinned verdicts
+
+**Details:**
+
+Update TaskService:
+1. recordVerdict(taskId, stage, agentId, commit, passed, summary, findings): create TaskVerdict row
+2. If !passed: transition task back to in_progress, create TaskEvent explaining why
+3. Determine required stages based on Task.risk:
+   - trivial: may pass on light self-check (no mandatory QA/Security/SRE)
+   - normal: requires qa_review
+   - high: requires qa_review + security_review + sre_review
+4. Verdicts are immutable - append only, pinned to commit SHA
+5. Each stage persona decides its own depth (not enforced in code, just recorded)
+6. Transition to done only when all required stages have passing verdicts for current headCommit
+
+**Test Strategy:**
+
+Unit tests: test verdict creation, test failed verdict transitions back to in_progress, test risk-based stage requirements.