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/teams/model.py

@@ -0,0 +1,97 @@
+"""Work-item model for agent teams — states, actors, links, errors.
+
+The board is not a database of record: it is a projection of the append-only team
+event log (see teams.store). These are the shapes the projection folds into, and the
+rules the verbs enforce. Deliberately minimal — no sprints, estimates, priorities, or
+custom fields; anyone needing those graduates to a real tracker via connectors.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from enum import Enum
+from pathlib import Path
+
+
+class ItemState(str, Enum):
+    OPEN = "open"
+    IN_PROGRESS = "in_progress"
+    BLOCKED = "blocked"
+    REVIEW = "review"
+    DONE = "done"
+    CANCELED = "canceled"
+
+
+# Legal edges of the state machine. There is NO draft/proposed state (decided
+# 2026-08-16): a plan proposal lives in the conversation (plan-approval flow) and
+# the board only ever contains accepted work — items are created `open`, and the
+# control point for work starting is ASSIGNMENT (a granted, revocable authority),
+# not a per-item approval. review→done stays the verification gate; canceled→open
+# is reopen.
+EDGES: dict[ItemState, set[ItemState]] = {
+    ItemState.OPEN: {ItemState.IN_PROGRESS, ItemState.CANCELED},
+    ItemState.IN_PROGRESS: {ItemState.BLOCKED, ItemState.REVIEW, ItemState.CANCELED},
+    ItemState.BLOCKED: {ItemState.IN_PROGRESS, ItemState.CANCELED},
+    ItemState.REVIEW: {ItemState.DONE, ItemState.IN_PROGRESS, ItemState.CANCELED},
+    ItemState.DONE: set(),
+    ItemState.CANCELED: {ItemState.OPEN},
+}
+
+# Targets a worker may move its OWN item to. Workers never approve, never close:
+# done is the lead's verdict at review, cancel is a lead/user board decision.
+WORKER_TARGETS = {ItemState.IN_PROGRESS, ItemState.BLOCKED, ItemState.REVIEW}
+
+
+class Role(str, Enum):
+    USER = "user"
+    LEAD = "lead"
+    WORKER = "worker"
+    SYSTEM = "system"
+
+
+@dataclass(frozen=True)
+class Actor:
+    """Who is speaking to the board. `id` is the agent instance id ("user" for the
+    human); role decides verb authority — the capability firebreak in data form."""
+
+    id: str
+    role: Role
+    persona: str = ""
+    model: str = ""
+    session_id: str = ""
+
+
+LINK_KINDS = ("parent", "blocks")  # link(src, "parent", dst): dst is src's parent
+                                   # link(src, "blocks", dst): src blocks dst
+
+# `note` is any observation — the journal is not only for investigations. `raw` is
+# a capture (log excerpt, command output); reads skip raw unless asked, and large
+# payloads belong in a file the entry references.
+JOURNAL_KINDS = ("finding", "evidence", "decision", "note", "raw")
+
+# An entry body is an excerpt/summary, never a blob: oversized payloads make every
+# read (and replay) drag. Full captures live as files the entry points at.
+JOURNAL_BODY_LIMIT = 16_000
+
+
+def space_for_workspace(workspace: str | Path) -> str:
+    """Spaces are keyed to the project/workspace (boards are views over a space).
+    The resolved path is the one unambiguous local key; a display name is its
+    basename."""
+    return str(Path(workspace).expanduser().resolve())
+
+
+class BoardError(Exception):
+    """A verb call the board refuses — illegal transition, missing item, bad input."""
+
+
+class BoardNotFoundError(BoardError):
+    """A requested board object is missing or is not visible to the actor."""
+
+
+class AuthorityError(BoardError):
+    """The actor's role does not permit this verb on this item."""
+
+
+class ChainError(Exception):
+    """Hash-chain verification failed — the log was modified out of band."""