fix: stabilize knowledge chat and gateway startup
Summary
- Disable gateway auto-start unless explicitly enabled
- Improve chat abort cleanup and stale pause handling
- Improve knowledge admin auth errors
Verification
- npm run test -- tests/server/config.test.ts tests/server/knowledge-controller.test.ts tests/server/chat-run-socket-abort.test.ts
- npx tsc --noEmit -p packages/server/tsconfig.json