feat(admin-web, functions): overhaul music library and add AI genre classification

- admin-web: Added an "All Music" library view with search, genre, and status filters.
- admin-web: Converted Jobs view to use expandable cards instead of a split pane.
- admin-web: Added ability to delete individual tracks from a job.
- functions: Added new `youtube-classify` edge function to automatically categorize tracks using Gemini LLM.
- functions: Integrated AI genre classification during initial playlist import if no manual genre is provided.
- worker: Added `/classify` endpoint for the worker to securely interface with Gemini.
- scripts: Updated deployment script to include `GEMINI_API_KEY`.

supabase/functions/youtube-status/index.ts

@@ -13,11 +13,93 @@ Deno.serve(async (req: Request) => {
 
     const supabase = createServiceClient();
 
-    // ── DELETE: remove a job, its items, and storage files ─────
+    // ── DELETE: remove a job OR a single item ───────────────
     if (req.method === "DELETE") {
-      const { jobId } = await req.json();
+      const body = await req.json();
+      const { jobId, itemId } = body as { jobId?: string; itemId?: string };
+
+      // ── Delete a single track ──────────────────────────────
+      if (itemId && typeof itemId === "string") {
+        // Fetch the item to get its storage_path, status, and parent job_id
+        const { data: item, error: fetchErr } = await supabase
+          .from("download_items")
+          .select("*")
+          .eq("id", itemId)
+          .single();
+
+        if (fetchErr || !item) {
+          return new Response(JSON.stringify({ error: "Item not found" }), {
+            status: 404,
+            headers: { ...corsHeaders, "Content-Type": "application/json" },
+          });
+        }
+
+        // Remove audio file from storage if it exists
+        if (item.storage_path) {
+          const { error: storageError } = await supabase.storage
+            .from("workout-audio")
+            .remove([item.storage_path]);
+
+          if (storageError) {
+            console.error("Storage cleanup error:", storageError.message);
+            // Continue with DB deletion even if storage cleanup fails
+          }
+        }
+
+        // Delete the item row
+        const { error: deleteError } = await supabase
+          .from("download_items")
+          .delete()
+          .eq("id", itemId);
+
+        if (deleteError) {
+          throw new Error(`Failed to delete item: ${deleteError.message}`);
+        }
+
+        // Update the parent job counters
+        const decrement: Record<string, number> = { total_items: -1 };
+        if (item.status === "completed") {
+          decrement.completed_items = -1;
+        } else if (item.status === "failed") {
+          decrement.failed_items = -1;
+        }
+
+        // Fetch current job to compute new values (Supabase doesn't support atomic decrement)
+        const { data: parentJob } = await supabase
+          .from("download_jobs")
+          .select("total_items, completed_items, failed_items")
+          .eq("id", item.job_id)
+          .single();
+
+        if (parentJob) {
+          const updates: Record<string, number> = {
+            total_items: Math.max(0, parentJob.total_items + (decrement.total_items ?? 0)),
+          };
+          if (decrement.completed_items) {
+            updates.completed_items = Math.max(0, parentJob.completed_items + decrement.completed_items);
+          }
+          if (decrement.failed_items) {
+            updates.failed_items = Math.max(0, parentJob.failed_items + decrement.failed_items);
+          }
+
+          await supabase
+            .from("download_jobs")
+            .update(updates)
+            .eq("id", item.job_id);
+        }
+
+        return new Response(
+          JSON.stringify({ deleted: true, itemId, jobId: item.job_id }),
+          {
+            status: 200,
+            headers: { ...corsHeaders, "Content-Type": "application/json" },
+          }
+        );
+      }
+
+      // ── Delete an entire job ───────────────────────────────
       if (!jobId || typeof jobId !== "string") {
-        return new Response(JSON.stringify({ error: "jobId is required" }), {
+        return new Response(JSON.stringify({ error: "jobId or itemId is required" }), {
           status: 400,
           headers: { ...corsHeaders, "Content-Type": "application/json" },
         });