feat(feishu): add scan-to-create onboarding for Feishu / Lark
Add a QR-based onboarding flow to `hermes gateway setup` for Feishu / Lark.
Users scan a QR code with their phone and the platform creates a fully
configured bot application automatically — matching the existing WeChat
QR login experience.
Setup flow:
- Choose between QR scan-to-create (new app) or manual credential input (existing app)
- Connection mode selection (WebSocket / Webhook)
- DM security policy (pairing / open / allowlist / disabled)
- Group chat policy (open with @mention / disabled)
Implementation:
- Onboard functions (init/begin/poll/QR/probe) in gateway/platforms/feishu.py
- _setup_feishu() in hermes_cli/gateway.py with manual fallback
- probe_bot uses lark_oapi SDK when available, raw HTTP fallback otherwise
- qr_register() catches expected errors (network/protocol), propagates bugs
- Poll handles HTTP 4xx JSON responses and feishu/lark domain auto-detection
Tests:
- 25 tests for onboard module (registration, QR, probe, contract, negative paths)
- 16 tests for setup flow (credentials, connection mode, DM policy, group policy,
adapter integration verifying env vars produce valid FeishuAdapterSettings)
Change-Id: I720591ee84755f32dda95fbac4b26dc82cbcf823