user-local installs for claude and pi, fix sandbox mounts

Move claude and pi from sudo global installs to ~/.local. Claude
binary is copied to /usr/local/bin for sandbox visibility, pi runs
via node from ~/.local/lib (ro-mounted). Fix bwrap intermediate dir
traversal by setting 0755 perms on auto-created HOME dirs.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/servers/sidecar/sandbox.ts

@@ -65,9 +65,21 @@ export function buildSandboxPrefix(email: string): string[] {
   if (existsSync('/lib64')) args.push('--ro-bind', '/lib64', '/lib64');
   if (existsSync('/sbin')) args.push('--ro-bind', '/sbin', '/sbin');
 
+  // Ensure intermediate dirs under HOME are traversable after runuser drops privileges
+  // (bwrap auto-creates them as root-owned drwx------)
+  const homeDir = process.env.HOME!;
+  args.push('--perms', '0755', '--dir', homeDir);
+
   // Bun runtime (e.g. /home/pastilhas/.bun)
   args.push('--ro-bind', BUN_DIR, BUN_DIR);
 
+  // npm global packages (~/.local/lib) — pi and its dependencies
+  const localLib = join(homeDir, '.local', 'lib');
+  if (existsSync(localLib)) {
+    args.push('--perms', '0755', '--dir', join(homeDir, '.local'));
+    args.push('--ro-bind', localLib, localLib);
+  }
+
   // Project source (for MCP server)
   args.push('--ro-bind', PROJECT_ROOT, PROJECT_ROOT);