fix(dashcam): wrap action buttons in div, ffmpeg stream for MOV playback

- local-videos.js: action buttons go in a div.data-list-actions inside td
  so td stays a table cell (not flex); thumbnail td gets fixed width 9rem
- app.py: video route now pipes ffmpeg with -c copy -movflags
  frag_keyframe+empty_moov so browsers get a fragmented MP4 stream that
  starts playing immediately without needing the moov atom at the end

Co-authored-by: Copilot <[email protected]>

app.py

@@ -1,6 +1,6 @@
 from flask import Flask, render_template, make_response, json, jsonify, request, send_file, Response
 from modules import app_gps, app_events, app_car, app_account, app_gps,app_obd, app_sql, app_dash, app_upload, app_video, app_health, app_alerts, app_settings, app_network
-import os, time
+import os, time, subprocess
 from gevent.pywsgi import WSGIServer
 
 
@@ -150,48 +150,30 @@ def local_video_file():
     except FileNotFoundError:
         return jsonify(error=f"Local video not found: {relative_path}"), 404
 
-    ext = os.path.splitext(path)[1].lower()
-    mime_map = {".mp4": "video/mp4", ".mov": "video/quicktime", ".avi": "video/x-msvideo", ".mkv": "video/x-matroska"}
-    mime = mime_map.get(ext, "video/mp4")
-
-    file_size = os.path.getsize(path)
-    range_header = request.headers.get("Range")
-
-    if range_header:
-        m = range_header.strip().replace("bytes=", "").split("-")
-        byte1 = int(m[0]) if m[0] else 0
-        byte2 = int(m[1]) if len(m) > 1 and m[1] else file_size - 1
-        byte2 = min(byte2, file_size - 1)
-        length = byte2 - byte1 + 1
-
-        def generate_range():
-            with open(path, "rb") as f:
-                f.seek(byte1)
-                remaining = length
-                while remaining > 0:
-                    chunk = f.read(min(65536, remaining))
-                    if not chunk:
-                        break
-                    remaining -= len(chunk)
-                    yield chunk
-
-        resp = Response(generate_range(), 206, mimetype=mime, direct_passthrough=True)
-        resp.headers["Content-Range"] = f"bytes {byte1}-{byte2}/{file_size}"
-        resp.headers["Accept-Ranges"] = "bytes"
-        resp.headers["Content-Length"] = str(length)
-        return resp
-
-    def generate_full():
-        with open(path, "rb") as f:
+    # Stream via ffmpeg: copy streams into an MP4 container with moov atom first
+    # so browsers can start playback immediately without downloading the whole file.
+    def generate_stream():
+        cmd = [
+            "ffmpeg", "-nostdin", "-loglevel", "error",
+            "-i", path,
+            "-c", "copy",           # no re-encode, just remux
+            "-movflags", "frag_keyframe+empty_moov+faststart",
+            "-f", "mp4",
+            "pipe:1",
+        ]
+        proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.DEVNULL)
+        try:
             while True:
-                chunk = f.read(65536)
+                chunk = proc.stdout.read(65536)
                 if not chunk:
                     break
                 yield chunk
+        finally:
+            proc.stdout.close()
+            proc.wait()
 
-    resp = Response(generate_full(), 200, mimetype=mime, direct_passthrough=True)
-    resp.headers["Accept-Ranges"] = "bytes"
-    resp.headers["Content-Length"] = str(file_size)
+    resp = Response(generate_stream(), 200, mimetype="video/mp4", direct_passthrough=True)
+    resp.headers["Cache-Control"] = "no-cache"
     return resp
 
 @app.route('/api/local-video/thumbnail')