feat(gateway): add Feishu/Lark platform support (#3817)

Adds Feishu (ByteDance's enterprise messaging platform) as a gateway
platform adapter with full feature parity: WebSocket + webhook transports,
message batching, dedup, rate limiting, rich post/card content parsing,
media handling (images/audio/files/video), group @mention gating,
reaction routing, and interactive card button support.

Cherry-picked from PR #1793 by penwyp with:
- Moved to current main (PR was 458 commits behind)
- Fixed _send_with_retry shadowing BasePlatformAdapter method (renamed to
  _feishu_send_with_retry to avoid signature mismatch crash)
- Fixed import structure: aiohttp/websockets imported independently of
  lark_oapi so they remain available when SDK is missing
- Fixed get_hermes_home import (hermes_constants, not hermes_cli.config)
- Added skip decorators for tests requiring lark_oapi SDK
- All 16 integration points added surgically to current main

New dependency: lark-oapi>=1.5.3,<2 (optional, pip install hermes-agent[feishu])

Fixes #1788

Co-authored-by: penwyp <penwyp@users.noreply.github.com>

pyproject.toml

@@ -58,6 +58,7 @@ homeassistant = ["aiohttp>=3.9.0,<4"]
 sms = ["aiohttp>=3.9.0,<4"]
 acp = ["agent-client-protocol>=0.8.1,<0.9"]
 dingtalk = ["dingtalk-stream>=0.1.0,<1"]
+feishu = ["lark-oapi>=1.5.3,<2"]
 rl = [
   "atroposlib @ git+https://github.com/NousResearch/atropos.git",
   "tinker @ git+https://github.com/thinking-machines-lab/tinker.git",
@@ -83,6 +84,7 @@ all = [
   "hermes-agent[acp]",
   "hermes-agent[voice]",
   "hermes-agent[dingtalk]",
+  "hermes-agent[feishu]",
 ]
 
 [project.scripts]