fix: update innertube clients and fix HLS/DASH quality switching

- Update innertube client versions to match yt-dlp (android 21.02.35,
  ios 21.02.3, web 2.20260114.08.00, android_vr 1.65.10)
- Remove obsolete clients (android-test-suite, ios_vr)
- Replace tv_embedded with TVHTML5_SIMPLY (cn 75)
- Add new clients: web_embedded, mweb, tv
- Fix HLS freeze on quality switch: use nextLevel instead of
  currentLevel, handle bufferStalledError, stream proxy segments
  instead of buffering in memory
- Populate DASH quality selector with actual sources (no Auto)
- Render quality-select empty in template, let JS populate per mode

youtube/watch.py

@@ -17,8 +17,16 @@ from flask import request
 import youtube
 from youtube import yt_app
 from youtube import util, comments, local_playlist, yt_data_extract
+from youtube import watch_formats
 import settings
 
+# Backward compatibility aliases
+codec_name = watch_formats.codec_name
+video_quality_string = watch_formats.video_quality_string
+short_video_quality_string = watch_formats.short_video_quality_string
+audio_quality_string = watch_formats.audio_quality_string
+format_bytes = watch_formats.format_bytes
+
 logger = logging.getLogger(__name__)
 
 
@@ -29,15 +37,7 @@ except FileNotFoundError:
     decrypt_cache = {}
 
 
-def codec_name(vcodec):
-    if vcodec.startswith('avc'):
-        return 'h264'
-    elif vcodec.startswith('av01'):
-        return 'av1'
-    elif vcodec.startswith('vp'):
-        return 'vp'
-    else:
-        return 'unknown'
+# codec_name imported from watch_formats
 
 
 def get_video_sources(info, target_resolution):
@@ -446,7 +446,7 @@ def extract_info(video_id, use_invidious, playlist_id=None, index=None):
     info['hls_audio_tracks'] = {}
     hls_data = None
     hls_client_used = None
-    for hls_client in ('ios', 'ios_vr', 'android'):
+    for hls_client in ('ios', 'android'):
         try:
             resp = fetch_player_response(hls_client, video_id) or {}
             hls_data = json.loads(resp) if isinstance(resp, str) else resp
@@ -621,55 +621,10 @@ def extract_info(video_id, use_invidious, playlist_id=None, index=None):
     return info
 
 
-def video_quality_string(format):
-    if format['vcodec']:
-        result = f"{format['width'] or '?'}x{format['height'] or '?'}"
-        if format['fps']:
-            result += f" {format['fps']}fps"
-        return result
-    elif format['acodec']:
-        return 'audio only'
-
-    return '?'
-
-
-def short_video_quality_string(fmt):
-    result = f"{fmt['quality'] or '?'}p"
-    if fmt['fps']:
-        result += str(fmt['fps'])
-    if fmt['vcodec'].startswith('av01'):
-        result += ' AV1'
-    elif fmt['vcodec'].startswith('avc'):
-        result += ' h264'
-    else:
-        result += f" {fmt['vcodec']}"
-    return result
-
-
-def audio_quality_string(fmt):
-    if fmt['acodec']:
-        if fmt['audio_bitrate']:
-            result = f"{fmt['audio_bitrate']}k"
-        else:
-            result = '?k'
-        if fmt['audio_sample_rate']:
-            result += f" {'%.3G' % (fmt['audio_sample_rate']/1000)}kHz"
-        return result
-    elif fmt['vcodec']:
-        return 'video only'
-    return '?'
-
-
-# from https://github.com/ytdl-org/youtube-dl/blob/master/youtube_dl/utils.py
-def format_bytes(bytes):
-    if bytes is None:
-        return 'N/A'
-    if type(bytes) is str:
-        bytes = float(bytes)
-    if bytes == 0.0:
-        exponent = 0
-    else:
-        exponent = int(math.log(bytes, 1024.0))
+# video_quality_string imported from watch_formats
+# short_video_quality_string imported from watch_formats
+# audio_quality_string imported from watch_formats
+# format_bytes imported from watch_formats
     suffix = ['B', 'KiB', 'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 'ZiB', 'YiB'][exponent]
     converted = float(bytes) / float(1024 ** exponent)
     return '%.2f%s' % (converted, suffix)
@@ -832,14 +787,12 @@ def get_audio_track():
 
         # This is an actual segment - fetch and serve it
         try:
-            headers = (
-                ('User-Agent', 'Mozilla/5.0'),
-                ('Accept', '*/*'),
-            )
-            content = util.fetch_url(seg_url, headers=headers,
-                debug_name='hls_seg', report_text=None)
+            headers_dict = {
+                'User-Agent': 'Mozilla/5.0',
+                'Accept': '*/*',
+            }
 
-            # Determine content type based on URL or content
+            # Determine content type based on URL
             # HLS segments are usually MPEG-TS (.ts) but can be MP4 (.mp4, .m4s)
             if '.mp4' in seg_url or '.m4s' in seg_url or seg_url.lower().endswith('.mp4'):
                 content_type = 'video/mp4'
@@ -849,7 +802,23 @@ def get_audio_track():
                 # Default to MPEG-TS for HLS
                 content_type = 'video/mp2t'
 
-            return flask.Response(content, mimetype=content_type,
+            response, cleanup_func = util.fetch_url_response(
+                seg_url, headers=tuple(headers_dict.items()),
+                timeout=30, use_tor=settings.route_tor)
+
+            def generate():
+                try:
+                    while True:
+                        chunk = response.read(64 * 1024)  # 64 KB chunks
+                        if not chunk:
+                            break
+                        yield chunk
+                finally:
+                    cleanup_func(response)
+
+            return flask.Response(
+                flask.stream_with_context(generate()),
+                mimetype=content_type,
                 headers={
                     'Access-Control-Allow-Origin': '*',
                     'Access-Control-Allow-Methods': 'GET, OPTIONS',