wip(k1): checkpoint connection recovery rewrite

Capture the current unreleased K1 connection, recovery, lifecycle, viewer, and test work as a single known-bad baseline for subsequent fixes.

src/k1link/web/app.py

@@ -11,7 +11,6 @@ from typing import Any
 from fastapi import FastAPI, HTTPException, Request, WebSocket, WebSocketDisconnect
 from fastapi.exceptions import RequestValidationError
 from fastapi.responses import JSONResponse
-from fastapi.staticfiles import StaticFiles
 from pydantic import ValidationError
 from starlette.middleware.gzip import GZipMiddleware
 
@@ -76,6 +75,7 @@ from k1link.web.e46j_raw_fisheye_realtime_api import (
 )
 from k1link.web.e47_semantic_slam_api import build_e47_semantic_slam_router
 from k1link.web.environment_api import build_environment_router
+from k1link.web.frontend_assets import ControlStationStaticFiles, frontend_build_id
 from k1link.web.l3_pointpillars_visual_api import (
     build_l3_pointpillars_visual_router,
 )
@@ -385,7 +385,7 @@ async def _recording_preparation_reconciler() -> None:
 async def app_lifespan(_: FastAPI) -> AsyncIterator[None]:
     reconciler: asyncio.Task[None] | None = None
     try:
-        configure_scanner_diagnostics(REPOSITORY_ROOT / ".runtime" / "mission-core" / "logs")
+        configure_scanner_diagnostics(session_store.data_dir / "logs")
         session_recording_preparation_manager.start()
         # Recovery is intentionally a one-shot startup phase. The archive
         # helper owns a cross-process lease, while ordinary catalog requests
@@ -480,11 +480,36 @@ async def invoke_device_plugin_action(
     except ValueError as exc:
         raise HTTPException(status_code=400, detail=str(exc)) from exc
     except PluginExecutionError as exc:
-        raise HTTPException(status_code=502, detail=str(exc)) from exc
+        raise HTTPException(status_code=exc.http_status_code, detail=str(exc)) from exc
     except PluginRuntimeUnavailableError as exc:
         raise HTTPException(status_code=503, detail=str(exc)) from exc
 
 
+_CLOSED_WEBSOCKET_SEND_ERRORS = frozenset(
+    {
+        "handler is closed",
+        'Cannot call "send" once a close message has been sent.',
+        (
+            "Unexpected ASGI message 'websocket.send', after sending "
+            "'websocket.close' or response already completed."
+        ),
+    }
+)
+
+
+def _is_closed_websocket_send_error(exc: RuntimeError) -> bool:
+    message = " ".join(str(exc).split())
+    if message in _CLOSED_WEBSOCKET_SEND_ERRORS:
+        return True
+    # uvloop raises this after the browser has already torn down the TCP
+    # transport, before Starlette can translate the failed send into a
+    # WebSocketDisconnect. Match both stable parts so an unrelated RuntimeError
+    # containing only "closed" is never swallowed.
+    return message.startswith("unable to perform operation on ") and message.endswith(
+        "; the handler is closed"
+    )
+
+
 @app.websocket("/api/v1/device-plugins/{plugin_id}/events")
 async def device_plugin_events(websocket: WebSocket, plugin_id: str) -> None:
     await websocket.accept()
@@ -493,10 +518,17 @@ async def device_plugin_events(websocket: WebSocket, plugin_id: str) -> None:
         while True:
             state = await plugin_dispatcher.invoke(plugin_id, STATE_READ_ACTION_ID, {})
             sequence += 1
-            await websocket.send_json({"pluginId": plugin_id, "sequence": sequence, "state": state})
+            try:
+                await websocket.send_json(
+                    {"pluginId": plugin_id, "sequence": sequence, "state": state}
+                )
+            except WebSocketDisconnect:
+                return
+            except RuntimeError as exc:
+                if _is_closed_websocket_send_error(exc):
+                    return
+                raise
             await asyncio.sleep(0.5)
-    except WebSocketDisconnect:
-        return
     except (PluginNotFoundError, PluginActionNotFoundError):
         await websocket.close(code=1008, reason="Device plugin is not available")
     except (PluginExecutionError, PluginRuntimeUnavailableError):
@@ -781,11 +813,7 @@ app.include_router(
 app.include_router(
     build_e47_semantic_slam_router(
         root_provider=lambda: (
-            REPOSITORY_ROOT
-            / ".runtime"
-            / "compute-experiments"
-            / "e47"
-            / "semantic-slam-results"
+            REPOSITORY_ROOT / ".runtime" / "compute-experiments" / "e47" / "semantic-slam-results"
         ),
     )
 )
@@ -1114,9 +1142,17 @@ app.include_router(
         root_provider=lambda: REPOSITORY_ROOT / ".runtime" / "system",
     )
 )
-app.include_router(build_viewer_diagnostics_router())
-
-
 frontend_dist = REPOSITORY_ROOT / "apps" / "control-station" / "dist"
+app.include_router(
+    build_viewer_diagnostics_router(
+        expected_ui_build_id=lambda: frontend_build_id(frontend_dist),
+    )
+)
+
+
 if frontend_dist.is_dir():
-    app.mount("/", StaticFiles(directory=frontend_dist, html=True), name="frontend")
+    app.mount(
+        "/",
+        ControlStationStaticFiles(directory=frontend_dist, html=True),
+        name="frontend",
+    )