feat: initial CamWatch service

Polls Frigate events API, extracts dominant vehicle color (KMeans),
reads LPR plate from Frigate sub_label. Responsive dark UI with
filter by plate/camera/date and auto-refresh. FastAPI + SQLite.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/main.py

@@ -0,0 +1,100 @@
+import os
+import logging
+import threading
+from contextlib import asynccontextmanager
+from fastapi import FastAPI, Request, Query
+from fastapi.responses import HTMLResponse, FileResponse
+from fastapi.staticfiles import StaticFiles
+from fastapi.templating import Jinja2Templates
+from datetime import datetime
+
+import database
+import watcher
+
+logging.basicConfig(level=logging.INFO, format="%(asctime)s %(name)s %(levelname)s %(message)s")
+
+DATA_DIR = os.environ.get("SNAPSHOTS_DIR", "/data/snapshots")
+os.makedirs(DATA_DIR, exist_ok=True)
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    database.init_db()
+    t = threading.Thread(target=watcher.run_watcher, daemon=True)
+    t.start()
+    yield
+
+
+app = FastAPI(lifespan=lifespan)
+app.mount("/snapshots", StaticFiles(directory="/data/snapshots"), name="snapshots")
+
+templates = Jinja2Templates(directory="/app/templates")
+
+
+def ts_to_str(ts):
+    try:
+        return datetime.fromtimestamp(ts).strftime("%d/%m/%Y %H:%M:%S")
+    except Exception:
+        return str(ts)
+
+
+@app.get("/", response_class=HTMLResponse)
+async def index(
+    request: Request,
+    page: int = Query(1, ge=1),
+    plate: str = Query(""),
+    camera: str = Query(""),
+    date: str = Query(""),
+):
+    limit = 20
+    offset = (page - 1) * limit
+    events = database.get_events(limit=limit, offset=offset,
+                                  plate_filter=plate or None,
+                                  camera_filter=camera or None,
+                                  date_filter=date or None)
+    total = database.count_events(plate_filter=plate or None,
+                                   camera_filter=camera or None,
+                                   date_filter=date or None)
+    cameras = database.get_cameras()
+    total_pages = max(1, (total + limit - 1) // limit)
+
+    for ev in events:
+        ev["time_str"] = ts_to_str(ev["start_time"])
+
+    return templates.TemplateResponse("index.html", {
+        "request": request,
+        "events": events,
+        "total": total,
+        "page": page,
+        "total_pages": total_pages,
+        "cameras": cameras,
+        "filter_plate": plate,
+        "filter_camera": camera,
+        "filter_date": date,
+    })
+
+
+@app.get("/api/events")
+async def api_events(
+    page: int = Query(1, ge=1),
+    plate: str = Query(""),
+    camera: str = Query(""),
+    date: str = Query(""),
+):
+    limit = 20
+    offset = (page - 1) * limit
+    events = database.get_events(limit=limit, offset=offset,
+                                  plate_filter=plate or None,
+                                  camera_filter=camera or None,
+                                  date_filter=date or None)
+    total = database.count_events(plate_filter=plate or None,
+                                   camera_filter=camera or None,
+                                   date_filter=date or None)
+    for ev in events:
+        ev["time_str"] = ts_to_str(ev["start_time"])
+    return {"events": events, "total": total}
+
+
+@app.get("/health")
+async def health():
+    return {"status": "ok"}