feat: OpenMesh 基础平台与 MD/PDF 转换技能

- 后端: coworker 智能体框架, WS API, 文件上传, 附件处理
- 前端: Open WebUI, 文件全量走 upload API (含 MD/TXT/JSON 等文本类)
- 技能: md-to-office (pandoc + wkhtmltopdf)
- 修复: 上传文件路径丢失, Agent 搜索浪费, 输出文件跑到 uploads/
- 打包: PyInstaller one-dir, 预打包 pandoc/wkhtmltopdf/chromium

coworker/connectors/slack_addr.py

@@ -0,0 +1,34 @@
+"""Slack team-qualified addressing for managed relay (slack-relay-spec §8/§9).
+
+A single owner can be in several Slack workspaces at once, so a bare channel id
+(`C…`) is ambiguous — a `U…`/`C…` only means something inside its `team_id`.
+Managed-relay targets therefore carry the team: the reply handle's chat_id is
+`"{team_id}/{channel}"`.
+
+Encoding note: the reply-target grammar is colon-delimited
+(`platform:chat_id[:thread]`, see base.parse_target), so we join team+channel
+with `/` — colon-free — to stay inside that grammar unchanged. `slack:T012345/C0123`
+is the wire form of the spec's conceptual `slack:T012345:C0123`. Manual
+Socket-Mode targets (single workspace) keep the bare `slack:C0123` form.
+"""
+
+from __future__ import annotations
+
+from typing import Optional
+
+
+def qualify(team_id: Optional[str], channel: str) -> str:
+    """Build a team-qualified chat_id, or the bare channel when no team."""
+    return f"{team_id}/{channel}" if team_id else channel
+
+
+def split(chat_id: str) -> tuple[Optional[str], str]:
+    """`'T…/C…' -> ('T…', 'C…')`; a bare `'C…' -> (None, 'C…')`.
+
+    Only the first `/` splits (channel ids never contain one), so this is
+    lossless both ways.
+    """
+    if chat_id and "/" in chat_id:
+        team, _, channel = chat_id.partition("/")
+        return (team or None), channel
+    return None, chat_id