fix(feishu): keep bridge reactions best-effort

[GatewayJ]

Summary

• Make Feishu processing reactions asynchronous best-effort with bounded cleanup.
• Add context-aware Feishu update/reaction service paths and require room_id for local update consistency.
• Cover update fallback and reaction add/delete failure paths with regression tests.

Validation

• make fmt
• git diff --check
• go test -count=1 ./internal/channel/feishu ./internal/channelbridge/codexbridge
• go test -count=10 ./internal/channelbridge/codexbridge -run 'FeishuProcessingPin|GeneratedRootUpdate'

Notes

• Full go test ./... still has existing internal/api failures unrelated to this change: TestDirectoryPickerCanceled and TestHandleAgentsPatchFieldMaskClearsRuntimeOptions.