fix(podcasts): page search hits episode titles/descriptions (issue #8)

WHY: the /podcasts search box filtered feed CARDS only (title, display
name, host, publisher, feed description). D14's episode search existed
only as the /api/podcasts/search endpoint and was never wired into the
page — searching 'Quarter' (present only in episode titles) cleared the
grid while 'Trader' (feed metadata) survived.

The page query now consults SearchMyPodcastEpisodes (subscription-scoped
via RLS — the caller's identity) when a query is present; a feed
surfaces when its OWN metadata OR any of its episodes matches, with an
'N matching episode(s)' badge on the card.

PIN: SSR test with a needle that exists only in an episode title — the
feed must surface with the match count.

templates/podcast_types.go

@@ -44,6 +44,11 @@ type PodcastFeedCard struct {
 	AutoDownloadCount int
 	Subscribed        bool
 
+	// EpisodeMatches (issue #8): when a search query is active, the
+	// number of the feed's episodes whose title/description matched —
+	// feeds match on EPISODES too, not just their own metadata.
+	EpisodeMatches int
+
 	// Continue aggregation (plan 2.5): the episode the user is midway
 	// through, most recent first across feeds.
 	HasContinue      bool
@@ -174,6 +179,14 @@ func podcastInt(n int) string {
 	return fmt.Sprintf("%d", n)
 }
 
+// podcastPlural returns "" for 1 and "s" otherwise.
+func podcastPlural(n int) string {
+	if n == 1 {
+		return ""
+	}
+	return "s"
+}
+
 // timeStringPtr helper: display-format with empty fallback.
 func podcastTimeOrEmpty(t time.Time, valid bool, tz string) string {
 	if !valid || t.IsZero() {