feat(feishu): replace built-in SDK with community plugin

Replace the built-in Feishu SDK with the community-maintained
clawdbot-feishu plugin by @m1heng.

Changes:
- Remove src/feishu/ directory (19 files)
- Remove src/channels/plugins/outbound/feishu.ts
- Remove src/channels/plugins/normalize/feishu.ts
- Remove src/config/types.feishu.ts
- Remove feishu exports from plugin-sdk/index.ts
- Remove FeishuConfig from types.channels.ts

New features in community plugin:
- Document tools (read/create/edit Feishu docs)
- Wiki tools (navigate/manage knowledge base)
- Drive tools (folder/file management)
- Bitable tools (read/write table records)
- Permission tools (collaborator management)
- Emoji reactions support
- Typing indicators
- Rich media support (bidirectional image/file transfer)
- @mention handling
- Skills for feishu-doc, feishu-wiki, feishu-drive, feishu-perm

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/channels/plugins/normalize/feishu.ts

@@ -1,5 +0,0 @@
-export function normalizeFeishuTarget(raw: string): string {
-  let normalized = raw.replace(/^(feishu|lark):/i, "").trim();
-  normalized = normalized.replace(/^(group|chat|user|dm):/i, "").trim();
-  return normalized;
-}