feat(podcasts): chain playback + Continue section — sequence mode in the web player (phase 2 core)

D7 chain-by-default, delivered with minimal player surgery:

- ReaderMetadata gains PodcastSequence: the neighboring DOWNLOADED
  episodes in the caller's effective order (D5 override applied,
  feed-native fallback; computed in the reader route for
  source='podcast_episode' items — RLS already scoped the reads; gaps
  never enter the chain, invariant 6). ?single=1 escapes chaining (the
  'play single episode' affordance).
- Audio reader renders the sequence into body[data-json]
  (AudioReaderConfigJSON — books produce the identical shape minus the
  sequence key, so the reader path is unchanged for them) and an
  'Ep N/M' indicator + prev/next episode controls in the header.
- audio.ts: the last-track 'ended' handler chains into the next
  episode's reader page (final progress push precedes navigation);
  back button exits episodes to their feed page. Books are untouched —
  no sequence context, zero behavior change. Day-one chaining is
  page-navigation based (progress persists; position restores).

Continue aggregation (2.5): GetPodcastContinueForUser (in-progress
episodes, most-recent-first, ≥95% excluded) feeds a Continue section
on /podcasts — sorted most recently listened, cards show 'Ep N · title'
— ahead of All Feeds. Cards prefer the continue line over the
description.

templates/podcasts.templ

@@ -67,7 +67,7 @@ templ PodcastsPage(user User, data PodcastsPageData, currentPath string) {
 							<p class="text-sm" style="color: var(--text-secondary)">Add an RSS feed to start listening — episodes land here and download on demand.</p>
 						</div>
 					} else {
-						@PodcastsGrid(data.Feeds)
+						@PodcastsSections(data)
 					}
 				}
 			</main>
@@ -115,6 +115,22 @@ templ PodcastsFilterBar(data PodcastsPageData) {
 	}
 }
 
+// PodcastsSections renders the Continue section (feeds with in-progress
+// episodes, most recently listened first — plan 2.5) ahead of the
+// alphabetical All Feeds grid.
+templ PodcastsSections(data PodcastsPageData) {
+	if len(data.ContinueFeeds) > 0 {
+		<h2 class="text-lg font-bold mb-3 mt-2" style="color: var(--text-primary)">Continue</h2>
+		<div class="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 xl:grid-cols-4 gap-4 mb-8">
+			for _, feed := range data.ContinueFeeds {
+				@PodcastFeedCardView(feed)
+			}
+		</div>
+		<h2 class="text-lg font-bold mb-3" style="color: var(--text-primary)">All Feeds</h2>
+	}
+	@PodcastsGrid(data.Feeds)
+}
+
 templ PodcastsGrid(feeds []PodcastFeedCard) {
 	<div class="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 xl:grid-cols-4 gap-4">
 		for _, feed := range feeds {
@@ -151,7 +167,12 @@ templ PodcastFeedCardView(feed PodcastFeedCard) {
 				</p>
 			</div>
 		</div>
-		if feed.Description != "" {
+		if feed.HasContinue {
+			<p class="text-xs font-medium line-clamp-1" style="color: var(--accent)">
+				@Icon("book-open", "h-3.5 w-3.5 inline")
+				{ " " + podcastInt(feed.ContinueEpisode) + ". " + feed.ContinueTitle }
+			</p>
+		} else if feed.Description != "" {
 			<p class="text-xs line-clamp-2" style="color: var(--text-secondary)">{ feed.Description }</p>
 		}
 		<div class="mt-auto flex flex-wrap items-center gap-1.5 text-xs">