feat: add lark (feishu) interface

[yipingw]

Summary

Adds a Lark (Feishu) interface to AgentOS, enabling agents/teams/workflows to be reached via Lark bot event subscriptions. Mirrors the existing Telegram/Slack/WhatsApp interface patterns.

Key features:

• Webhook-based event subscription (POST /lark/webhook) with AES-256-CBC event decryption and SHA-256 signature verification (when encrypt_key is configured)
• Streaming responses via interactive cards (PATCH /im/v1/messages/:id), with progressive card updates as tokens arrive
• Non-streaming responses via interactive cards (markdown rendering)
• Group chat @mention gating (reply_to_mentions_only)
• Per-chat session tracking (lark:{entity_id}:{chat_id})
• Inbound media (image/file/audio/video) and outbound media (image/file)
• Built-in /new (session reset) and /help commands
• Event dedup (Lark retries if not ACKed within 3s)
• Works with Agent, Team, and Workflow
• Supports both Feishu (open.feishu.cn) and Lark (open.larksuite.com) domains

Type of change

• New feature

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Checklist

• Code complies with style guidelines
• Ran format/validation scripts (ruff format, ruff check, mypy all pass)
• Self-review completed
• Documentation updated (docstrings, cookbook README)
• Examples and guides: cookbook example included (cookbook/05_agent_os/interfaces/lark/)
• Tested in clean environment (end-to-end tested with a real Feishu app)
• Tests added/updated (N/A — interface requires live platform credentials)

Duplicate and AI-Generated PR Check

• I have searched existing open pull requests and confirmed that no other PR already addresses this issue
• Check if this PR was entirely AI-generated: Yes, developed with AI assistance

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Additional Notes

End-to-end tested with a real Feishu custom app:

• Group chat @mention: verified (event → decrypt → verify → DeepSeek agent → streaming card reply)
• Private chat (P2P): verified (requires im:message.p2p_msg:readonly permission)
• URL verification challenge: verified
• AES encryption + SHA-256 signature verification: verified

The interface uses raw httpx (no SDK dependency), matching the WhatsApp interface's lightweight approach. Optional AES decryption requires pip install 'agno[lark-crypto]' (cryptography>=41.0).

[github-actions]

PR Triage

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Missing tests: This PR modifies source code but does not include any test changes. Please add or update tests to cover your changes.