fix(podcast): address CodeRabbit review feedback

- Remove total HTTP client timeout from episode downloads (use transport
  phase timeouts instead) and delete partial files on failure
- Keep SSE progress listener subscribed while the show view is mounted
- Return podcastEpisode (with streamId) from getNewestPodcasts
- Clean up dependent rows and MediaFiles in DeleteChannel within a tx
- Limit RSS feed body size to 32 MiB
- Block additional reserved IP ranges in the SSRF guard
- Fall back to enclosure URL when an item has no <guid>
- Handle clipboard write failure in the podcast list

ui/src/i18n/en.json

@@ -299,6 +299,7 @@
         "downloadStarted": "Download started",
         "channelAdded": "Channel added",
         "urlCopied": "Feed URL copied to clipboard",
+        "urlCopyFailed": "Could not copy the feed URL",
         "alreadyExists": "This channel is already registered.",
         "channelDeleted": "Channel deleted",
         "episodeDeleted": "Episode deleted"

ui/src/podcast/PodcastList.jsx

@@ -70,8 +70,10 @@ const FeedUrlField = ({ record }) => {
   if (!record?.url) return null
   const handleCopy = (e) => {
     e.stopPropagation()
-    navigator.clipboard.writeText(record.url)
-    notify('resources.podcast.notifications.urlCopied')
+    navigator.clipboard
+      .writeText(record.url)
+      .then(() => notify('resources.podcast.notifications.urlCopied'))
+      .catch(() => notify('resources.podcast.notifications.urlCopyFailed', 'warning'))
   }
   return (
     <span style={{ display: 'flex', alignItems: 'center', gap: 4 }}>

ui/src/podcast/PodcastShow.jsx

@@ -124,10 +124,9 @@ const PodcastShow = (props) => {
 
   useEffect(loadEpisodes, [record?.id])
 
-  // Subscribe to SSE progress only while episodes are downloading
-  const hasDownloading = episodes.some((ep) => ep.status === 'downloading')
+  // Stay subscribed to SSE progress while the view is mounted: a download
+  // started from here may not be flagged 'downloading' yet when we refresh.
   useEffect(() => {
-    if (!hasDownloading) return
     const handler = (e) => {
       const { episodeId, downloadedBytes, size, duration, status } = e.detail
       if (status === 'completed' || status === 'error') {
@@ -145,7 +144,7 @@ const PodcastShow = (props) => {
     }
     window.addEventListener('podcastEpisodeProgress', handler)
     return () => window.removeEventListener('podcastEpisodeProgress', handler)
-  }, [hasDownloading])
+  }, [record?.id])
 
   if (!record) return null