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_061.md

@@ -0,0 +1,49 @@
+# Task ID: 61
+
+**Title:** Update CLI describe project command for gated status
+
+**Status:** done
+
+**Dependencies:** 44 ✓, 54 ✓
+
+**Priority:** medium
+
+**Description:** Extend mcpctl describe project to show gated status, session greeting, and prompt table with priority and link information.
+
+**Details:**
+
+1. Update `/src/cli/src/commands/get.ts` describe project:
+   ```typescript
+   async function describeProject(name: string) {
+     const project = await api.get(`/api/v1/projects/${name}`);
+     const prompts = await api.get(`/api/v1/projects/${name}/prompt-index`);
+     const greeting = await getSessionGreeting(name);
+     
+     console.log(`Name:         ${project.name}`);
+     console.log(`Gated:        ${project.gated}`);
+     console.log(`LLM Provider: ${project.llmProvider || '-'}`);
+     console.log(`...`);
+     console.log();
+     console.log(`Session greeting:`);
+     console.log(`  ${greeting}`);
+     console.log();
+     console.log(`Prompts:`);
+     console.log(`  NAME                 PRIORITY  TYPE    LINK`);
+     for (const p of prompts) {
+       const type = p.linkTarget ? 'link' : 'local';
+       const link = p.linkTarget || '-';
+       console.log(`  ${p.name.padEnd(20)} ${p.priority.toString().padEnd(9)} ${type.padEnd(7)} ${link}`);
+     }
+   }
+   ```
+
+2. Fetch session greeting from system prompts or project config
+
+**Test Strategy:**
+
+- Unit test: Gated status displayed
+- Unit test: Session greeting displayed
+- Unit test: Prompt table with PRIORITY, TYPE, LINK columns
+- Unit test: TYPE shows 'local' or 'link'
+- Unit test: LINK shows target or -
+- Integration test: End-to-end describe project