feat: redesign YouTube stats tracking with Supabase pipeline

- Replace Sanity-based youtubeUpdateTask queue with Supabase youtube_stats table
- New 3-phase pipeline: discover → fetch → sync (lib/youtube-stats.ts)
- Route reduced from 349 to 54 lines (85% reduction)
- Sanity only written to when stats actually change
- Remove youtubeUpdateTask schema, types, and config references
- Add Supabase migration for youtube_stats table with indexes and RPC
- Update cron route to forward ?action= param for phase-specific runs
- Add cleanup route to delete existing youtubeUpdateTask documents
- Add architecture documentation

Co-authored-by: youtubeviews <youtubeviews@miriad.systems>

Author: Miriad

app/api/cron/route.tsx

@@ -12,7 +12,10 @@ export function GET(request: NextRequest) {
 		});
 	}
 	try {
-		const url = `${publicURL()}/api/youtube/views`;
+		// Forward the action param if present (discover, fetch, sync)
+		const action = request.nextUrl.searchParams.get("action");
+		const params = action ? `?action=${action}` : "";
+		const url = `${publicURL()}/api/youtube/views${params}`;
 		console.log("[CRON] Triggering YouTube views update:", url);
 		fetch(url, {
 			method: "POST",

app/api/youtube/cleanup/route.tsx

@@ -0,0 +1,70 @@
+/**
+ * One-time cleanup script: Delete all youtubeUpdateTask documents from Sanity.
+ * 
+ * Run via: POST /api/youtube/cleanup
+ * Auth: Bearer CRON_SECRET
+ * 
+ * DELETE THIS FILE after running it once.
+ */
+export const fetchCache = "force-no-store";
+
+import { createClient } from "next-sanity";
+import type { NextRequest } from "next/server";
+import { apiVersion, dataset, projectId } from "@/sanity/lib/api";
+
+const sanityWriteClient = createClient({
+	projectId,
+	dataset,
+	apiVersion,
+	token: process.env.SANITY_API_TOKEN || process.env.SANITY_API_WRITE_TOKEN,
+	perspective: "published",
+	useCdn: false,
+});
+
+export async function POST(request: NextRequest) {
+	const authHeader = request.headers.get("authorization");
+	if (authHeader !== `Bearer ${process.env.CRON_SECRET}`) {
+		return new Response("Unauthorized", { status: 401 });
+	}
+
+	try {
+		// Count existing tasks
+		const count = await sanityWriteClient.fetch(
+			`count(*[_type == "youtubeUpdateTask"])`
+		);
+		console.log(`[CLEANUP] Found ${count} youtubeUpdateTask documents to delete`);
+
+		if (count === 0) {
+			return Response.json({ success: true, deleted: 0, message: "No documents to delete" });
+		}
+
+		// Delete in batches of 100
+		let totalDeleted = 0;
+		while (true) {
+			const tasks: { _id: string }[] = await sanityWriteClient.fetch(
+				`*[_type == "youtubeUpdateTask"][0...100]{ _id }`
+			);
+
+			if (!tasks || tasks.length === 0) break;
+
+			// Use transaction for batch delete
+			const tx = sanityWriteClient.transaction();
+			for (const task of tasks) {
+				tx.delete(task._id);
+			}
+			await tx.commit({ visibility: "async" });
+
+			totalDeleted += tasks.length;
+			console.log(`[CLEANUP] Deleted batch of ${tasks.length} (total: ${totalDeleted})`);
+		}
+
+		console.log(`[CLEANUP] Done. Deleted ${totalDeleted} youtubeUpdateTask documents.`);
+		return Response.json({ success: true, deleted: totalDeleted });
+	} catch (error) {
+		console.error("[CLEANUP] Error:", error);
+		return Response.json(
+			{ success: false, error: String(error) },
+			{ status: 500 }
+		);
+	}
+}