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/providers/router.py

@@ -0,0 +1,118 @@
+"""ProviderRouter — one `ProviderClient` that dispatches by the `provider:` prefix of a model
+string to a per-provider client, built lazily from its SecretStore profile and cached.
+
+This is the single provider the `SessionManager` hands to every engine, so `complete()/stream()`
+(which already receive the full model string per-call) route themselves: `ollama:llama3.3` →
+the Ollama client (Ollama's OpenAI-compatible `/v1`), bare `gpt-5.5` → the default (OpenAI). The
+prefix is stripped before delegating, since the underlying SDKs want the bare model name.
+
+Config changes (a new key, a new Ollama URL) call `invalidate()` to drop cached clients, so
+existing engines pick up the change without a rebuild.
+"""
+
+from __future__ import annotations
+
+import threading
+from typing import Any, Optional
+
+from .base import ProviderClient
+from .capabilities import capabilities_for
+from .registry import build_provider_client, get_descriptor
+
+
+class ProviderRouter(ProviderClient):
+    def __init__(
+        self,
+        secrets: Any = None,
+        *,
+        default_provider: str = "openai",
+        on_use: Any = None,
+    ) -> None:
+        self._secrets = secrets
+        self._default = default_provider
+        self._clients: dict[str, ProviderClient] = {}
+        self._lock = threading.Lock()
+        # Optional callable(provider_name) fired when a completion is dispatched — drives the
+        # Settings pane's "Last used" line. Best-effort: its failures never break a model call.
+        self._on_use = on_use
+
+    def _note_use(self, model: str) -> None:
+        if self._on_use is None:
+            return
+        try:
+            self._on_use(self._provider_name(model))
+        except Exception:
+            pass
+
+    # -- routing ----------------------------------------------------------------
+    def _provider_name(self, model: str) -> str:
+        """The provider for a model: the `prefix` of `prefix:rest` if it's a known provider,
+        else the default. (A colon that isn't a known provider — unlikely — falls through.)
+        """
+        if ":" in model:
+            prefix = model.split(":", 1)[0]
+            if get_descriptor(prefix) is not None:
+                return prefix
+        return self._default
+
+    def _client_for(self, model: str) -> ProviderClient:
+        name = self._provider_name(model)
+        with self._lock:
+            client = self._clients.get(name)
+            if client is None:
+                profile = {}
+                if self._secrets is not None:
+                    profile = self._secrets.get(f"provider:{name}") or {}
+                client = build_provider_client(name, profile, self._secrets)
+                self._clients[name] = client
+            return client
+
+    @staticmethod
+    def _bare(model: str) -> str:
+        """Strip a KNOWN provider prefix; the underlying SDK wants the bare model name. A model
+        whose first segment isn't a provider (e.g. `qwen2.5-coder:32b` — a version tag, not a
+        prefix) is returned unchanged, so the colon isn't mistaken for a provider separator.
+        """
+        if ":" in model:
+            prefix, rest = model.split(":", 1)
+            if get_descriptor(prefix) is not None:
+                return rest
+        return model
+
+    def invalidate(self, name: Optional[str] = None) -> None:
+        """Drop cached client(s) so the next call rebuilds with fresh config."""
+        with self._lock:
+            if name is None:
+                self._clients.clear()
+            else:
+                self._clients.pop(name, None)
+
+    # -- ProviderClient ---------------------------------------------------------
+    def complete(
+        self,
+        *,
+        model: str,
+        messages: list[dict[str, Any]],
+        tools: Optional[list[dict[str, Any]]] = None,
+        **settings: Any,
+    ):
+        self._note_use(model)
+        return self._client_for(model).complete(
+            model=self._bare(model), messages=messages, tools=tools, **settings
+        )
+
+    def stream(
+        self,
+        *,
+        model: str,
+        messages: list[dict[str, Any]],
+        tools: Optional[list[dict[str, Any]]] = None,
+        **settings: Any,
+    ):
+        self._note_use(model)
+        return self._client_for(model).stream(
+            model=self._bare(model), messages=messages, tools=tools, **settings
+        )
+
+    def capabilities(self, model: str):
+        return capabilities_for(model)