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/sessions.py

@@ -0,0 +1,46 @@
+"""Session record — the metadata + messages for one conversation.
+
+Storage lives in `coworker.conversations.ConversationStore`: a SQLite index keyed by
+project, with each conversation's messages in an append-only `.jsonl` file.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+from typing import Any, Optional
+
+
+@dataclass
+class SessionRecord:
+    session_id: str
+    workspace: str
+    model: str
+    mode: str
+    messages: list[dict[str, Any]] = field(default_factory=list)
+    title: Optional[str] = None
+    agent: str = "code"
+    message_count: int = 0
+    updated_at: Optional[str] = None
+    # Folders added to the session beyond its primary scratch dir, each {path, writable, label}.
+    # The primary scratch is re-provisioned at engine build, so only these extras are persisted.
+    extra_roots: list[dict[str, Any]] = field(default_factory=list)
+    # "Always allow" approvals granted in this session ({tools: [...], commands: [...]}) —
+    # session-scoped by design, but the session outlives the process, so they must too
+    # (owner-hit 2026-07-22: grants forgotten on every restart).
+    grants: dict[str, Any] = field(default_factory=dict)
+    pinned: bool = False
+    archived: bool = False
+    # Where the session came from, when not user-started (§31): machine key + display label
+    # (e.g. origin="slack", origin_label="#general · T0ABCD"). Set once at spawn.
+    origin: Optional[str] = None
+    origin_label: Optional[str] = None
+    # Auto-compaction state (OPE-27): CompactionState.as_dict(), {} when never compacted.
+    # Persisted so a reloaded session keeps its compacted outbound view.
+    compaction: dict[str, Any] = field(default_factory=dict)
+    # Twentieth pass: explicit per-session project bindings, {} = derive from the
+    # workspace. Keys "memory" / "board", values = names in project_names.
+    bindings: dict[str, Any] = field(default_factory=dict)
+    # Agent teams: {} for plain sessions. Workers: {team_id, role: "worker", actor,
+    # lead_session, space}. Leads gain their entry when the staffing gate creates the
+    # team. Drives tool binding (board actor identity) + the sidebar's expandable entry.
+    team: dict[str, Any] = field(default_factory=dict)