chore: remove container legacy references

- Delete container/build.sh (Docker build script, no longer used)
- Remove "auth" npm script (whatsapp-auth.ts doesn't exist)
- Remove CONTAINER_* env var fallbacks from config.ts
- Update CLAUDE.md: container-runner → agent-runner, fix descriptions
- Rename MAX_CONCURRENT_CONTAINERS → MAX_CONCURRENT_AGENTS in systemd

package.json

@@ -15,7 +15,6 @@
     "format:check": "prettier --check \"src/**/*.ts\"",
     "prepare": "husky",
     "setup": "tsx setup/index.ts",
-    "auth": "tsx src/whatsapp-auth.ts",
     "test": "vitest run",
     "test:watch": "vitest"
   },