feat: add Feishu/Lark connector with webhook event ingestion

[joezhoujinjing]

Summary

• Implements Feishu/Lark connector backend (FeishuConnectorBackend) with dual auth model (bot tenant_access_token + user OAuth via OAuthConnectorMixin)
• Adds webhook router at POST /api/v2/webhooks/feishu for inbound event ingestion with challenge verification and EventBus publishing
• Registers connector in backends registry, service map, OAuth config, and pyproject.toml (lark-oapi dependency)

Details

Connector (Task #82 + #84):

• VFS mount structure: /mnt/feishu/groups/{name}.yaml and /mnt/feishu/p2p/{name}.yaml
• list_dir fetches chats from Feishu API, read_content returns messages as YAML, write_content sends messages via API
• Supports YAML/JSON write format: msg_type: text + content: {text: "hello"}
• Cache support via CacheConnectorMixin

Webhook (Task #83):

• URL verification challenge handling (Feishu setup handshake)
• Event token + signature verification
• Event mapping: im.message.receive_v1 → FILE_WRITE, im.chat.member.bot.added_v1 → DIR_CREATE, im.chat.member.bot.deleted_v1 → DIR_DELETE
• Publishes FileEvent to EventBus for downstream processing

Test plan

• E2E tested list_chats — 11 chats returned from real Feishu workspace
• E2E tested list_messages_from_chat — messages fetched from real chat
• E2E tested send_message — message delivered to Feishu group
• E2E tested full connector list_dir, read_content, write_content flow
• Tested webhook challenge response
• Tested event mapping (3 event types + unknown)
• Tested EventBus publishing with mock bus
• Integration test with VFS mount (manual)

🤖 Generated with Claude Code

[joezhoujinjing]

Technical Lead Review: Real-Time Cache Invalidation Strategy

The implementation correctly follows the 'Proxy-with-Cache' philosophy, but there is a consistency gap between the webhook ingestion and the VFS read path.

Problem:
The router publishes events, but the is currently unaware of these events. This means an agent reading a chat file might see stale data from the even after a new message has arrived via webhook.

Requested Solution:
Please implement a Cache Invalidation Loop:

1. Subscribe: The should subscribe to events matching its mount prefix.
2. Invalidate: When an event is received for a chat path (e.g., ), the backend should call .
3. Consistency: This ensures the next call bypasses the stale cache and fetches the latest state from the Feishu SSOT.

This closes the loop between 'Real-Time Events' and 'Filesystem Reads,' ensuring our AI agents always operate on the most current reality.

[joezhoujinjing]

Technical Lead Review: Real-Time Cache Invalidation Strategy

The implementation correctly follows the 'Proxy-with-Cache' philosophy, but there is a consistency gap between the webhook ingestion and the VFS read path.

Problem:
The feishu_webhook router publishes FILE_WRITE events, but the FeishuConnectorBackend is currently unaware of these events. This means an agent reading a chat file might see stale data from the CacheConnectorMixin even after a new message has arrived via webhook.

Requested Solution:
Please implement a Cache Invalidation Loop:

1. Subscribe: The FeishuConnectorBackend should subscribe to FILE_WRITE events matching its mount prefix.
2. Invalidate: When an event is received for a chat path (e.g., /mnt/feishu/groups/{id}.yaml), the backend should call self._invalidate_cache(path).
3. Consistency: This ensures the next read_content call bypasses the stale cache and fetches the latest state from the Feishu SSOT.

This closes the loop between 'Real-Time Events' and 'Filesystem Reads,' ensuring our AI agents always operate on the most current reality.

[joezhoujinjing]

Technical Lead Refactor: Semantic Prefix & Hybrid Naming Strategy

After architectural review, we are shifting the Feishu VFS structure to a more robust and semantically clear model. Please refactor the implementation with the following changes:

1. New Prefix: Change the mount prefix from /mnt/feishu/ to /chat/feishu/. This aligns with our 'Unified Messaging OS' philosophy.
2. Hybrid Naming Scheme: Filenames must use the pattern {Name} [{ID}].yaml (e.g., General [oc_123].yaml).
   • Requirement: list_dir must append the ID in brackets.
   • Requirement: read_content and write_content must parse the ID from the brackets to ensure persistent resolution even if the chat is renamed.
3. Webhook Alignment: Update the feishu_webhook.py router to map inbound events to the new /chat/feishu/ paths.

This change ensures that AI agent 'links' to these files remain stable over time and that the filesystem remains human-readable.