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_085.md

@@ -0,0 +1,65 @@
+# Task ID: 85
+
+**Title:** Implement Hot-Reload for Stages
+
+**Status:** done
+
+**Dependencies:** 79 ✓
+
+**Priority:** medium
+
+**Description:** Add file watching for ~/.mcpctl/stages/ to automatically reload custom stages when they change without restarting mcplocal.
+
+**Details:**
+
+Modify `src/mcplocal/src/proxymodel/stage-registry.ts`:
+
+```typescript
+import { watch, FSWatcher } from 'fs';
+import { join, basename } from 'path';
+
+let watcher: FSWatcher | null = null;
+const stageFileHashes: Map<string, string> = new Map();
+
+export function startStageWatcher(): void {
+  if (watcher) return;
+  
+  try {
+    watcher = watch(STAGES_DIR, async (eventType, filename) => {
+      if (!filename || (!filename.endsWith('.ts') && !filename.endsWith('.js'))) return;
+      
+      const name = filename.replace(/\.(ts|js)$/, '');
+      const fullPath = join(STAGES_DIR, filename);
+      
+      if (eventType === 'rename') {
+        // File added or removed
+        await loadCustomStages();
+        console.info(`[proxymodel] Stages reloaded due to ${filename} change`);
+      } else if (eventType === 'change') {
+        // File modified - invalidate module cache and reload
+        delete require.cache[require.resolve(fullPath)];
+        try {
+          const module = await import(fullPath + '?t=' + Date.now());
+          customStages.set(name, module.default);
+          console.info(`[proxymodel] Stage '${name}' hot-reloaded`);
+        } catch (err) {
+          console.error(`[proxymodel] Failed to reload stage '${name}':`, err);
+        }
+      }
+    });
+  } catch {
+    // Directory doesn't exist - no watching needed
+  }
+}
+
+export function stopStageWatcher(): void {
+  watcher?.close();
+  watcher = null;
+}
+```
+
+Call startStageWatcher() during mcplocal initialization.
+
+**Test Strategy:**
+
+Integration tests: modify a stage file and verify the new version is loaded without restart, add a new stage file and verify it becomes available, remove a stage file and verify it's no longer available, syntax errors in stage file don't crash the watcher.