fix: remaining npm→pnpm gaps + dockerignore for pnpm symlinks

- container/.dockerignore (new): exclude agent-runner/node_modules and
  agent-runner/dist so COPY agent-runner/ ./ doesn't clobber the
  pnpm-installed node_modules with host directories. Under npm's flat
  layout this was forgiving; under pnpm's symlink layout it's a hard
  conflict (overlay2 cannot copy onto a symlink target).
- setup/{groups,service}.ts: execSync('pnpm run build') not npm.
- setup/index.ts: usage string.
- scripts/*.ts: usage comments + seed-discord final log.
- .claude/settings.json: permission allowlist entries.
- .claude/skills/{add-whatsapp-v2,add-dashboard}/SKILL.md: docs.
- container/skills/{frontend-engineer,vercel-cli,self-customize}/SKILL.md:
  agent-facing docs still told the container agent to run npm.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

setup/service.ts

@@ -31,7 +31,7 @@ export async function run(_args: string[]): Promise<void> {
   // Build first
   log.info('Building TypeScript');
   try {
-    execSync('npm run build', {
+    execSync('pnpm run build', {
       cwd: projectRoot,
       stdio: ['ignore', 'pipe', 'pipe'],
     });