remove yt-dlp, fix captions PO Token issue, fix 429 retry logic

- Remove yt-dlp entirely (modules, routes, settings, dependency)
  Was blocking page loads by running synchronously in gevent
- Fix captions: use Android client caption URLs (no PO Token needed)
  instead of web timedtext URLs that YouTube now blocks
- Fix 429 retry: fail immediately without Tor (same IP = pointless retry)
  Was causing ~27s delays with exponential backoff
- Accept ytdlp_enabled as legacy setting to avoid warning on startup

youtube/util.py

@@ -367,34 +367,25 @@ def fetch_url(url, headers=(), timeout=15, report_text=None, data=None,
                                    response.getheader('Set-Cookie') or '')
                     ip = ip.group(1) if ip else None
 
-                # If this is the last attempt, raise error
+                # Without Tor, no point retrying with same IP
+                if not use_tor or not settings.route_tor:
+                    logger.warning('Rate limited (429). Enable Tor routing to retry with new IP.')
+                    raise FetchError('429', reason=response.reason, ip=ip)
+
+                # Tor: exhausted retries
                 if attempt >= max_retries - 1:
-                    if not use_tor or not settings.route_tor:
-                        logger.warning(f'YouTube returned 429 but Tor is not enabled. Consider enabling Tor routing.')
-                        raise FetchError('429', reason=response.reason, ip=ip)
-                    else:
-                        # Tor is enabled but we've exhausted retries
-                        logger.error(f'YouTube blocked request - Tor exit node overutilized after {max_retries} retries. Exit IP: {ip}')
-                        raise FetchError('429', reason=response.reason, ip=ip,
-                                        error_message='Tor exit node overutilized after multiple retries')
+                    logger.error(f'Rate limited after {max_retries} retries. Exit IP: {ip}')
+                    raise FetchError('429', reason=response.reason, ip=ip,
+                                    error_message='Tor exit node overutilized after multiple retries')
 
-                # For Tor: get new identity immediately on 429
-                if use_tor and settings.route_tor:
-                    logger.info(f'YouTube blocked request - Tor exit node overutilized. Exit IP: {ip}. Getting new identity...')
-
-                    error = tor_manager.new_identity(start_time)
-                    if error:
-                        raise FetchError(
-                            '429', reason=response.reason, ip=ip,
-                            error_message='Automatic circuit change: ' + error)
-                    else:
-                        continue  # retry with new identity
-
-                # For non-Tor: exponential backoff
-                delay = (base_delay * (2 ** attempt)) + random.uniform(0, 1)
-                logger.info(f'Rate limited (429). Waiting {delay:.1f}s before retry {attempt + 1}/{max_retries}...')
-                time.sleep(delay)
-                continue  # retry
+                # Tor: get new identity and retry
+                logger.info(f'Rate limited. Getting new Tor identity... (IP: {ip})')
+                error = tor_manager.new_identity(start_time)
+                if error:
+                    raise FetchError(
+                        '429', reason=response.reason, ip=ip,
+                        error_message='Automatic circuit change: ' + error)
+                continue  # retry with new identity
 
             # Check for client errors (400, 404) - don't retry these
             if response.status == 400: