feat(validation): v2 LLM dashboard validation — plugin, routes, services

Core implementation of the v2 LLM dashboard validation pipeline:
- LLM plugin with Path A (screenshots) and Path B (logs-only) execution
- Validation task management (CRUD, schedule, run)
- WebSocket task progress with Python 3.13 asyncio fix
- Cross-task runs listing (GET /validation-tasks/runs/all)
- RecordResponse schema for validation records
- JSON prompt helper, per-dashboard status aggregation
- Prompt templates with docs/git-commit/validation presets
- Migration: v2 validation models + description column
- Tests: plugin persistence, prompt templates, batch, payload, url

backend/src/app.py

@@ -25,6 +25,7 @@ from fastapi.responses import FileResponse, JSONResponse
 from fastapi.staticfiles import StaticFiles
 from starlette.middleware.base import BaseHTTPMiddleware
 from starlette.middleware.sessions import SessionMiddleware
+from typing import Any
 
 from alembic import command as alembic_command
 
@@ -52,8 +53,8 @@ from .api.routes import (
     storage,
     tasks,
     translate,
-    validation,
 )
+from .api.routes.validation_tasks import router as validation_tasks
 from .core.auth.security import get_password_hash
 from .core.cot_logger import seed_trace_id
 from .core.database import AuthSessionLocal, init_db
@@ -341,7 +342,6 @@ async def log_requests(request: Request, call_next):
 # @RELATION DEPENDS_ON -> [ReportsRouter]
 # @RELATION DEPENDS_ON -> [LlmRoutes]
 # @RELATION DEPENDS_ON -> [CleanReleaseV2Api]
-# @RELATION DEPENDS_ON -> [ValidationRoutes]
 # @RELATION DEPENDS_ON -> [MaintenanceRouter]
 # Include API routes
 app.include_router(auth.router)
@@ -366,7 +366,7 @@ app.include_router(profile.router)
 app.include_router(dataset_review.router)
 app.include_router(health.router)
 app.include_router(translate.router)
-app.include_router(validation.router, prefix="/api/validation", tags=["Validation"])
+app.include_router(validation_tasks, prefix="/api/validation-tasks", tags=["Validation Tasks"])
 app.include_router(maintenance.maintenance_router)
 # #endregion API_Routes
 # #region api.include_routers [C:1] [TYPE Action] [SEMANTICS routes, registration, api]
@@ -590,8 +590,10 @@ async def websocket_endpoint(
 
             # ── Main loop: listen on both log and status queues ──
             while True:
+                log_task = asyncio.create_task(log_queue.get())
+                status_task = asyncio.create_task(status_queue.get())
                 done, _ = await asyncio.wait(
-                    [log_queue.get(), status_queue.get()],
+                    [log_task, status_task],
                     return_when=asyncio.FIRST_COMPLETED,
                 )
                 for coro in done:
@@ -634,7 +636,11 @@ async def websocket_endpoint(
                         await asyncio.sleep(2)
         except (WebSocketDisconnect, StopIteration):
             if isinstance(StopIteration):
-                pass  # normal termination
+                # Task reached terminal state — close cleanly with code 1000
+                try:
+                    await websocket.close(code=1000, reason="Task completed")
+                except Exception:
+                    pass
             logger.reason(
                 "WebSocket client disconnected or stream ended",
                 extra={"task_id": task_id},