always run pi as the service user, drop the sudo -u branch

- the sandbox already drops privileges to the OS user (id -un), so pi-bridge was
  the only code path that switched to a per-user unix account
- the four accounts it targeted (andrepadez, john-wick, fedra, miguelbenoliel)
  are vestigial: created by scripts/provision-existing-users.sh, with no home
  dirs, no files, no processes. the only live account is pastilhas@officer.dev,
  which maps to the service user, so isServiceUser was always true and the
  sudo -u branch could never fire
- add TODO.md tracking the leftover username plumbing, the useradd script, known
  bugs (task-executor relative cwd, bootstrap pi EEXIST), and the ufw 9010 rule

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/servers/api/pi/pi-bridge.ts

@@ -12,7 +12,6 @@ import {
   getUserExtensionsDir,
   getGlobalToolsDir,
   getUserToolsDir,
-  toShellUsername,
 } from '../../data-path';
 import { logger } from './logger';
 
@@ -84,7 +83,6 @@ async function resolveApiKeyForModel(model: string): Promise<string | null> {
 
 type SpawnPiOptions = {
   sessionFile?: string;
-  username?: string;
   role?: string;
 };
 
@@ -121,43 +119,27 @@ export async function spawnPi(
 
   const homeDir = getHomeDirForRole(email, options?.role ?? null);
   const toolsDirs = [getGlobalToolsDir(), getUserToolsDir(email)].join(':');
-  const shellUsername = options?.username ?? toShellUsername('', email);
-
-  const isServiceUser = (options?.username ?? toShellUsername('', email)) === (process.env.USER ?? '');
 
   const env: Record<string, string> = {
-    HOME: homeDir,
+    HOME: process.env.HOME ?? '',
     OFFICER_USER_HOME: homeDir,
     OFFICER_USER_ROOT: join(DATA_PATH, email),
-    PI_CODING_AGENT_DIR: isServiceUser ? PI_CONFIG_DIR : join(homeDir, '.pi', 'agent'),
+    PI_CODING_AGENT_DIR: PI_CONFIG_DIR,
     PI_TOOLS_DIRS: toolsDirs,
     OFFICER_EMAIL_DB: join(DATA_PATH, email, 'emails.db'),
     TERM: 'xterm-256color',
     PATH: process.env.PATH ?? '',
   };
 
-  // For service user, keep real HOME so Pi finds its config
-  if (isServiceUser) {
-    env.HOME = process.env.HOME ?? '';
-  }
+  const proc = Bun.spawn(piArgs, {
+    cwd,
+    stdin: 'pipe',
+    stdout: 'pipe',
+    stderr: 'pipe',
+    env: { ...process.env, ...env },
+  });
 
-  const proc = isServiceUser
-    ? Bun.spawn(piArgs, {
-        cwd,
-        stdin: 'pipe',
-        stdout: 'pipe',
-        stderr: 'pipe',
-        env: { ...process.env, ...env },
-      })
-    : Bun.spawn(['sudo', '-u', shellUsername, 'env', ...Object.entries(env).map(([k, v]) => `${k}=${v}`), ...piArgs], {
-        cwd,
-        stdin: 'pipe',
-        stdout: 'pipe',
-        stderr: 'pipe',
-      });
-
-  logger.info('Spawned Pi as user', {
-    username: shellUsername,
+  logger.info('Spawned Pi', {
     model,
     skills: skillFlags.filter((f) => f !== '--skill').length,
     extensions: extensionFlags.filter((f) => f !== '--extension').length,