refactor: replace discover for-you swap with targeted htmx fragment

internal/anime/handler.go

@@ -256,7 +256,7 @@ func (h *AnimeHandler) HandleDiscoverForYou(c *gin.Context) {
 	watchlistMap := h.watchlistMapForAnimes(c.Request.Context(), userID, data.Animes)
 
 	data.Section = "ForYou"
-	data.Fragment = "discover_row"
+	data.Fragment = "discover_for_you_section"
 	data.WatchlistMap = watchlistMap
 	c.HTML(http.StatusOK, "discover.gohtml", data)
 }

templates/discover.gohtml

@@ -35,12 +35,12 @@
   </section>
 
   {{/* For You Section */}}
-  <section class="flex flex-col gap-4">
+  <section id="discover-for-you-section" class="flex flex-col gap-4">
     <div class="flex items-center justify-between">
       <h2 class="text-base font-normal text-foreground">For You</h2>
       <span class="text-sm text-foreground-muted">Based on your watchlist</span>
     </div>
-    <div hx-get="/api/discover/for-you" hx-trigger="load" hx-swap="outerHTML">
+    <div hx-get="/api/discover/for-you" hx-trigger="load" hx-target="#discover-for-you-section" hx-swap="outerHTML">
       {{template "discover_skeleton"}}
     </div>
   </section>
@@ -93,6 +93,22 @@
 </div>
 {{end}}
 
+{{define "discover_for_you_section"}}
+{{if gt (len .Animes) 0}}
+<section id="discover-for-you-section" class="flex flex-col gap-4">
+  <div class="flex items-center justify-between">
+    <h2 class="text-base font-normal text-foreground">For You</h2>
+    <span class="text-sm text-foreground-muted">Based on your watchlist</span>
+  </div>
+  <div class="grid gap-4 [grid-template-columns:repeat(auto-fit,minmax(160px,1fr))]">
+    {{range .Animes}}
+      {{template "anime_card" dict "Anime" . "WithActions" true "IsWatchlist" (index $.WatchlistMap .MalID)}}
+    {{end}}
+  </div>
+</section>
+{{end}}
+{{end}}
+
 {{define "discover_skeleton"}}
 <div class="discover-grid">
   {{range (seq 8)}}