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_090.md

@@ -0,0 +1,47 @@
+# Task ID: 90
+
+**Title:** Implement mcpctl get stages Command
+
+**Status:** cancelled
+
+**Dependencies:** 79 ✓
+
+**Priority:** medium
+
+**Description:** Add CLI command to list all available stages (built-in + custom) with source and LLM requirements.
+
+**Details:**
+
+Create `src/cli/src/commands/get-stages.ts`:
+
+```typescript
+import { Command } from 'commander';
+import { listStages } from 'mcplocal/proxymodel/stage-registry';
+import Table from 'cli-table3';
+
+const LLM_REQUIRING_STAGES = ['summarize', 'summarize-tree', 'enhance', 'compress'];
+
+export function registerGetStages(program: Command): void {
+  program
+    .command('get stages')
+    .description('List all available stages')
+    .action(async () => {
+      const stages = listStages();
+      
+      const table = new Table({
+        head: ['NAME', 'SOURCE', 'REQUIRES-LLM'],
+      });
+      
+      for (const stage of stages) {
+        const requiresLlm = LLM_REQUIRING_STAGES.includes(stage.name);
+        table.push([stage.name, stage.source, requiresLlm ? 'yes' : 'no']);
+      }
+      
+      console.log(table.toString());
+    });
+}
+```
+
+**Test Strategy:**
+
+CLI test: `mcpctl get stages` outputs table with expected columns. Test with only built-ins, test with custom stages in ~/.mcpctl/stages/, verify custom overrides show 'local' source.