feat: 打通全栈标注闭环、异步拆帧与模型状态

后端能力：

- 新增 Celery app、worker task、ProcessingTask 模型、/api/tasks 查询接口和 media_task_runner，将 /api/media/parse 改为创建后台任务并由 worker 执行 FFmpeg/OpenCV/pydicom 拆帧。

- 新增 Redis 进度事件模块和 FastAPI Redis pub/sub 订阅，将 worker 任务进度广播到 /ws/progress；Dashboard 后端概览接口改为聚合 projects/frames/annotations/templates/processing_tasks。

- 统一项目状态为 pending/parsing/ready/error，新增共享 status 常量，并让前端兼容归一化旧状态值。

- 扩展 AI 后端：新增 SAM registry、SAM2 真实运行状态、SAM3 状态检测与文本语义推理适配入口，以及 /api/ai/models/status GPU/模型状态接口。

- 补齐标注保存/更新/删除、COCO/PNG mask 导出相关后端契约和模板 mapping_rules 打包/解包行为。

前端能力：

- 新增运行时 API/WS 地址推导配置，前端 API 封装对齐 FastAPI 路由、字段映射、任务轮询、标注归档、导出下载和 AI 预测响应转换。

- Dashboard 改为读取 /api/dashboard/overview，并订阅 WebSocket progress/complete/error/status 更新解析队列和实时流转记录。

- 项目库导入视频/DICOM 后创建项目、上传媒体、触发异步解析并刷新真实项目列表。

- 工作区加载真实帧、无帧时触发解析任务、回显已保存标注、保存未归档 mask、更新 dirty mask、清空当前帧后端标注、导出 COCO JSON。

- Canvas 支持当前帧点/框提示调用后端 AI、渲染推理/已保存 mask、应用模板分类并维护保存状态计数；时间轴按项目 fps 播放。

- AI 页面新增 SAM2/SAM3 模型选择，预测请求携带 model；侧边栏和工作区新增真实 GPU/SAM 状态徽标。

- 模板库和本体面板接入真实模板 CRUD、分类编辑、拖拽排序、JSON 导入、默认腹腔镜分类和本地自定义分类选择。

测试与文档：

- 新增 Vitest 配置、前端测试 setup、API/config/websocket/store/组件测试，覆盖登录、项目库、Dashboard、Canvas、工作区、模型状态、时间轴、本体和模板库。

- 新增 pytest 后端测试夹具和 auth/projects/templates/media/AI/export/dashboard/tasks/progress 测试，使用 SQLite、fake MinIO、fake SAM registry 和 Redis monkeypatch 隔离外部服务。

- 新增 doc/ 文档结构，冻结当前需求、设计、接口契约、测试计划、前端逐元素审计、实现地图和后续实施计划，并同步更新 README 与 AGENTS。

验证：

- conda run -n seg_server pytest backend/tests：27 passed。

- npm run test:run：54 passed。

- npm run lint、npm run build、compileall、git diff --check 均通过；Vite 仅提示大 chunk 警告。

backend/main.py

@@ -1,11 +1,13 @@
 """FastAPI application entrypoint."""
 
 import asyncio
+import json
 import logging
 import os
 import shutil
 import tempfile
-from contextlib import asynccontextmanager
+from contextlib import asynccontextmanager, suppress
+from datetime import datetime, timezone
 
 from fastapi import FastAPI, WebSocket, WebSocketDisconnect
 from fastapi.middleware.cors import CORSMiddleware
@@ -13,9 +15,11 @@ from fastapi.middleware.cors import CORSMiddleware
 from config import settings
 from database import Base, engine, SessionLocal
 from minio_client import ensure_bucket_exists, upload_file
-from redis_client import ping as redis_ping
+from progress_events import PROGRESS_CHANNEL
+from redis_client import get_redis_client, ping as redis_ping
+from statuses import PROJECT_STATUS_PENDING, PROJECT_STATUS_READY
 
-from routers import projects, templates, media, ai, export, auth
+from routers import projects, templates, media, ai, export, auth, dashboard, tasks
 
 logging.basicConfig(
     level=logging.INFO,
@@ -45,7 +49,7 @@ def _seed_default_project_sync() -> None:
         project = Project(
             name="Data_MyVideo_1",
             description="默认演示视频",
-            status="pending",
+            status=PROJECT_STATUS_PENDING,
             source_type="video",
             parse_fps=30.0,
         )
@@ -98,7 +102,7 @@ def _seed_default_project_sync() -> None:
                 )
                 db.add(frame)
 
-            project.status = "ready"
+            project.status = PROJECT_STATUS_READY
             db.commit()
             logger.info("Seeded default project id=%s with %d frames", project.id, len(object_names))
         finally:
@@ -165,6 +169,7 @@ def _seed_default_templates_sync() -> None:
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     """Application lifespan: startup and shutdown hooks."""
+    progress_listener: asyncio.Task | None = None
     # Startup
     logger.info("Starting up SegServer backend...")
 
@@ -187,6 +192,11 @@ async def lifespan(app: FastAPI):
     else:
         logger.warning("Redis connection failed.")
 
+    try:
+        progress_listener = asyncio.create_task(_progress_pubsub_loop())
+    except Exception as exc:  # noqa: BLE001
+        logger.error("Failed to start Redis progress subscription: %s", exc)
+
     # Seed default templates
     try:
         asyncio.create_task(asyncio.to_thread(_seed_default_templates_sync))
@@ -203,6 +213,10 @@ async def lifespan(app: FastAPI):
 
     # Shutdown
     logger.info("Shutting down SegServer backend...")
+    if progress_listener is not None:
+        progress_listener.cancel()
+        with suppress(asyncio.CancelledError):
+            await progress_listener
     engine.dispose()
 
 
@@ -229,6 +243,8 @@ app.include_router(templates.router)
 app.include_router(media.router)
 app.include_router(ai.router)
 app.include_router(export.router)
+app.include_router(dashboard.router)
+app.include_router(tasks.router)
 
 
 @app.get("/health", tags=["Health"])
@@ -269,6 +285,34 @@ class ConnectionManager:
 manager = ConnectionManager()
 
 
+async def _progress_pubsub_loop() -> None:
+    """Forward Redis task-progress events to connected WebSocket clients."""
+    while True:
+        pubsub = None
+        try:
+            pubsub = get_redis_client().pubsub()
+            await asyncio.to_thread(pubsub.subscribe, PROGRESS_CHANNEL)
+            logger.info("Subscribed to Redis progress channel: %s", PROGRESS_CHANNEL)
+            while True:
+                message = await asyncio.to_thread(pubsub.get_message, True, 1.0)
+                if message is None:
+                    await asyncio.sleep(0)
+                    continue
+                raw_data = message.get("data")
+                payload = json.loads(raw_data) if isinstance(raw_data, str) else raw_data
+                if isinstance(payload, dict):
+                    await manager.broadcast(payload)
+        except asyncio.CancelledError:
+            raise
+        except Exception as exc:  # noqa: BLE001
+            logger.error("Redis progress subscription failed: %s", exc)
+            await asyncio.sleep(5)
+        finally:
+            if pubsub is not None:
+                with suppress(Exception):
+                    await asyncio.to_thread(pubsub.close)
+
+
 @app.websocket("/ws/progress")
 async def websocket_progress(websocket: WebSocket):
     """WebSocket endpoint for real-time parsing/AI progress updates."""
@@ -284,7 +328,7 @@ async def websocket_progress(websocket: WebSocket):
                 "type": "status",
                 "status": "connected",
                 "message": "Progress stream active",
-                "timestamp": str(logging.time.time() if hasattr(logging, 'time') else __import__('time').time()),
+                "timestamp": datetime.now(timezone.utc).isoformat(),
             })
     except WebSocketDisconnect:
         manager.disconnect(websocket)