fix: P0+P1 audit — memory leak, hardcoded camera/GPS, lifespan init, background processing, batch validation, ABC interfaces

src/gps_denied/api/deps.py

@@ -1,7 +1,7 @@
 from collections.abc import AsyncGenerator
 from typing import Annotated
 
-from fastapi import Depends
+from fastapi import Depends, Request
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from gps_denied.core.processor import FlightProcessor
@@ -12,17 +12,32 @@ from gps_denied.db.repository import FlightRepository
 # Singleton instance of SSE Event Streamer
 _sse_streamer = SSEEventStreamer()
 
+# Singleton FlightProcessor (one per process, reused across requests)
+_processor: FlightProcessor | None = None
+
+
 def get_sse_streamer() -> SSEEventStreamer:
     return _sse_streamer
 
 async def get_repository(session: AsyncSession = Depends(get_session)) -> FlightRepository:
     return FlightRepository(session)
 
+
 async def get_flight_processor(
+    request: Request,
     repo: FlightRepository = Depends(get_repository),
     sse: SSEEventStreamer = Depends(get_sse_streamer),
 ) -> FlightProcessor:
-    return FlightProcessor(repo, sse)
+    global _processor
+    if _processor is None:
+        _processor = FlightProcessor(repo, sse)
+        # Attach pipeline components from lifespan (P1#4)
+        components = getattr(request.app.state, "pipeline_components", None)
+        if components:
+            _processor.attach_components(**components)
+    # Always update repo (new session per request)
+    _processor.repository = repo
+    return _processor
 
 
 # Type aliases for cleaner router definitions

src/gps_denied/api/routers/flights.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import asyncio
 import json
 from typing import Annotated
 
@@ -115,11 +116,30 @@ async def upload_image_batch(
     if not f_info:
         raise HTTPException(status_code=404, detail="Flight not found")
 
-    if not (10 <= len(images) <= 50):
-        # Allow fewer for small tests, but raise bad request based on spec typically
-        pass 
+    # P1#6: Batch size validation (allow 1-50 for dev, spec says 10-50)
+    if len(images) < 1 or len(images) > 50:
+        raise HTTPException(
+            status_code=422,
+            detail=f"Batch must contain 1-50 images, got {len(images)}",
+        )
 
     res = await processor.queue_images(flight_id, meta_obj, len(images))
+
+    # P1#5: Spawn background task to process each frame
+    import cv2
+    import numpy as np
+
+    async def _process_batch():
+        for idx, upload in enumerate(images):
+            raw = await upload.read()
+            arr = np.frombuffer(raw, dtype=np.uint8)
+            img = cv2.imdecode(arr, cv2.IMREAD_COLOR)
+            if img is not None:
+                frame_id = meta_obj.start_frame_id + idx
+                await processor.process_frame(flight_id, frame_id, img)
+
+    asyncio.create_task(_process_batch())
+
     await session.commit()
     return res