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_100.md

@@ -0,0 +1,77 @@
+# Task ID: 100
+
+**Title:** Implement mcpctl cache list Command
+
+**Status:** done
+
+**Dependencies:** 98 ✓
+
+**Priority:** low
+
+**Description:** Add CLI command to list cached proxymodel artifacts with size and age information.
+
+**Details:**
+
+Create `src/cli/src/commands/cache-list.ts`:
+
+```typescript
+import { Command } from 'commander';
+import { readdir, stat } from 'fs/promises';
+import { join } from 'path';
+import Table from 'cli-table3';
+
+const CACHE_DIR = join(process.env.HOME ?? '', '.mcpctl', 'cache', 'proxymodel');
+
+export function registerCacheList(program: Command): void {
+  program
+    .command('cache list')
+    .description('List cached proxymodel artifacts')
+    .option('--project <name>', 'Filter by project')
+    .action(async (opts) => {
+      try {
+        const files = await readdir(CACHE_DIR);
+        
+        const table = new Table({
+          head: ['KEY', 'SIZE', 'AGE'],
+        });
+        
+        let totalSize = 0;
+        
+        for (const file of files) {
+          const filePath = join(CACHE_DIR, file);
+          const stats = await stat(filePath);
+          const age = formatAge(Date.now() - stats.mtimeMs);
+          const size = formatSize(stats.size);
+          totalSize += stats.size;
+          
+          if (opts.project && !file.includes(opts.project)) continue;
+          
+          table.push([file, size, age]);
+        }
+        
+        console.log(table.toString());
+        console.log(`Total: ${formatSize(totalSize)}`);
+      } catch {
+        console.log('No cache entries found');
+      }
+    });
+}
+
+function formatSize(bytes: number): string {
+  if (bytes < 1024) return `${bytes}B`;
+  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)}KB`;
+  return `${(bytes / 1024 / 1024).toFixed(1)}MB`;
+}
+
+function formatAge(ms: number): string {
+  const mins = Math.floor(ms / 60000);
+  if (mins < 60) return `${mins}m`;
+  const hours = Math.floor(mins / 60);
+  if (hours < 24) return `${hours}h`;
+  return `${Math.floor(hours / 24)}d`;
+}
+```
+
+**Test Strategy:**
+
+CLI test: list shows cache entries with correct format, --project filter works, empty cache shows appropriate message, size/age formatting is correct.