Fix Windows server shutdown after 60s from ffmpeg cleanup (#605)

On Windows, process.terminate() on ffmpeg broadcasts CTRL_C_EVENT to
  the entire process group, causing uvicorn to shut down. Spawn ffmpeg
  with CREATE_NEW_PROCESS_GROUP so cleanup doesn't affect the server.

CHANGELOG.md

@@ -4,6 +4,9 @@ All notable changes to Bambuddy will be documented in this file.
 
 ## [0.2.2b2] - Unreleased
 
+### Fixed
+- **Windows: Server Shuts Down After 60 Seconds** ([#605](https://github.com/maziggy/bambuddy/issues/605)) — On Windows, terminating orphaned ffmpeg camera processes broadcast `CTRL_C_EVENT` to the entire process group, causing uvicorn to interpret it as a user-initiated shutdown. ffmpeg is now spawned in its own process group (`CREATE_NEW_PROCESS_GROUP`) so cleanup no longer affects the server. Reported by @Reactantvr.
+
 ## [0.2.2b1] - 2026-03-03
 
 ### Improved

backend/app/api/routes/camera.py

@@ -2,6 +2,8 @@
 
 import asyncio
 import logging
+import subprocess
+import sys
 from collections.abc import AsyncGenerator
 
 from fastapi import APIRouter, Depends, HTTPException, Request
@@ -223,10 +225,17 @@ async def generate_rtsp_mjpeg_stream(
 
     process = None
     try:
+        # On Windows, spawn ffmpeg in its own process group so that
+        # terminate() doesn't broadcast CTRL_C_EVENT to uvicorn (#605).
+        kwargs: dict = {}
+        if sys.platform == "win32":
+            kwargs["creationflags"] = subprocess.CREATE_NEW_PROCESS_GROUP
+
         process = await asyncio.create_subprocess_exec(
             *cmd,
             stdout=asyncio.subprocess.PIPE,
             stderr=asyncio.subprocess.PIPE,
+            **kwargs,
         )
 
         # Track active process for cleanup