fix(podcasts): page-load polls during downloads; indeterminate bar slides

A fresh detail-page load while downloads were active rendered the
NON-polling episode container (PollingEpisodeList was only reachable
via the /episodes partial route after Refresh), so the page froze
until the user refreshed manually. PodcastDetailPage now picks the
variant the same way the route does — HasActiveDownloads selects the
every-2s poll container.

Also: the indeterminate progress bar (feeds without Content-Length,
e.g. Scribl) used animate-pulse, which fades in place and reads as
frozen; replaced with a sliding shimmer keyframe
(.podcast-progress-indeterminate, 33% sliver, translating -100% ->
300%) in input.css. The live MB counter stays.

§0 item 1.

templates/podcast_detail.templ

@@ -203,8 +203,17 @@ templ PodcastDetailPage(user User, data PodcastDetailData) {
 					</div>
 				}
 
-				<!-- Episode list (self-refreshing htmx partial) -->
-				@PodcastEpisodeList(data)
+				<!-- Episode list (self-refreshing htmx partial). Pick the
+				     polling variant at page-render time when downloads are
+				     active — otherwise a fresh page load mid-download
+				     renders the non-polling container and never updates
+				     (the polling variant was previously only reachable via
+				     the /episodes partial route). -->
+				if HasActiveDownloads(data.Episodes) {
+					@PodcastEpisodeListPolling(data)
+				} else {
+					@PodcastEpisodeList(data)
+				}
 			</main>
 			@PodcastUnsubscribeModal(data)
 		</body>
@@ -284,8 +293,8 @@ templ PodcastEpisodeRowView(ep PodcastEpisodeRow) {
 							{ FormatEpisodeSize(ep.ProgressReceived) + " / " + FormatEpisodeSize(ep.ProgressTotal) }
 						</p>
 					} else {
-						<div class="h-1.5 w-full rounded-full overflow-hidden animate-pulse" style="background-color: var(--surface-secondary);">
-							<div class="h-full w-1/3 rounded-full" style="background-color: var(--accent);"></div>
+						<div class="podcast-progress-indeterminate h-1.5 w-full rounded-full overflow-hidden" style="background-color: var(--surface-secondary);">
+							<div class="h-full rounded-full" style="background-color: var(--accent);"></div>
 						</div>
 						<p class="text-xs mt-0.5 tabular-nums" style="color: var(--text-secondary)">{ FormatEpisodeSize(ep.ProgressReceived) }</p>
 					}