Fix FFmpegVideoRemuxer typo and add launch.json dev server configs

- Fix 'preferedformat' → 'preferredformat' typo in consumers.py causing intermittent postprocessing failures when selecting custom formats
- Add .claude/launch.json with Frontend (Vite), Docker Full Stack, and Docker Backend+DB+Redis configurations

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

.claude/launch.json

@@ -0,0 +1,24 @@
+{
+  "version": "0.0.1",
+  "configurations": [
+    {
+      "name": "Frontend (Vite)",
+      "runtimeExecutable": "npm",
+      "runtimeArgs": ["run", "dev"],
+      "cwd": "frontend",
+      "port": 5173
+    },
+    {
+      "name": "Docker Stack (Full)",
+      "runtimeExecutable": "docker-compose",
+      "runtimeArgs": ["up"],
+      "port": 80
+    },
+    {
+      "name": "Docker Stack (Backend + DB + Redis)",
+      "runtimeExecutable": "docker-compose",
+      "runtimeArgs": ["up", "backend", "db", "redis"],
+      "port": 8000
+    }
+  ]
+}

backend/thirdparty/downloader/consumers.py

@@ -186,7 +186,7 @@ class DownloaderConsumer(AsyncWebsocketConsumer):
                 "preferredcodec": ext if ext in ("mp3", "m4a", "opus", "vorbis", "wav") else "mp3",
             })
         else:
-            ydl_opts["postprocessors"].append({"key": "FFmpegVideoRemuxer", "preferedformat": ext})
+            ydl_opts["postprocessors"].append({"key": "FFmpegVideoRemuxer", "preferredformat": ext})
 
         # Probe to detect playlist
         probe_opts = {**YDL_BASE, "extract_flat": False}