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/fake.py

@@ -0,0 +1,57 @@
+"""FakeAdapter — an in-memory platform for tests and the `cli fake` REPL.
+
+Lets you inject inbound messages programmatically and inspect what was sent, so the gateway
+and handler loop can be exercised end-to-end with no network or real tokens.
+"""
+
+from __future__ import annotations
+
+from typing import Optional
+
+from .base import BasePlatformAdapter, MessageEvent, SendResult, SessionSource
+
+
+class FakeAdapter(BasePlatformAdapter):
+    platform = "fake"
+
+    def __init__(self) -> None:
+        super().__init__()
+        self.connected = False
+        self.outbox: list[dict] = []  # {chat_id, text, thread_id}
+
+    async def connect(self) -> bool:
+        self.connected = True
+        return True
+
+    async def disconnect(self) -> None:
+        self.connected = False
+
+    async def send(
+        self, chat_id: str, text: str, *, thread_id: Optional[str] = None
+    ) -> SendResult:
+        self.outbox.append({"chat_id": chat_id, "text": text, "thread_id": thread_id})
+        return SendResult(True, message_id=str(len(self.outbox)))
+
+    # -- test/dev helpers -------------------------------------------------------
+    async def inject(
+        self,
+        text: str,
+        *,
+        chat_id: str = "c1",
+        user_id: str = "u1",
+        user_name: str = "tester",
+        chat_type: str = "dm",
+        thread_id: Optional[str] = None,
+    ) -> None:
+        """Simulate an inbound message arriving from the platform."""
+        source = SessionSource(
+            platform=self.platform,
+            chat_id=chat_id,
+            user_id=user_id,
+            user_name=user_name,
+            chat_type=chat_type,
+            thread_id=thread_id,
+        )
+        await self.handle_message(
+            MessageEvent(text=text, source=source, message_id=f"m{user_id}")
+        )