Build OverSnitch dashboard

Full implementation on top of the Next.js scaffold:

- Leaderboard with per-user request count, storage, avg GB/req, and
  optional Tautulli watch stats (plays, watch hours), each with dense
  per-metric rank (#N/total)
- SWR cache on /api/stats (5-min stale, force-refresh via button);
  client-side localStorage seed so the UI is instant on return visits
- Alerting system: content-centric alerts (unfulfilled downloads,
  partial TV downloads, stale pending requests) and user-behavior
  alerts (ghost requester, low watch rate, declined streak)
- Partial TV detection: flags ended series with <90% of episodes on disk
- Alert persistence in data/alerts.json with open/closed state,
  auto-resolve when condition clears, manual close with per-category
  cooldown, and per-alert notes
- Alert detail page rendered as a server component for instant load
- Dark UI with Tailwind v4, severity-colored left borders, summary
  cards with icons, sortable leaderboard table

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/api/alerts/[id]/comments/route.ts

@@ -0,0 +1,26 @@
+import { addComment } from "@/lib/db";
+
+export async function POST(
+  req: Request,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  const { id } = await params;
+
+  let body: { body: string };
+  try {
+    body = await req.json();
+  } catch {
+    return Response.json({ error: "Invalid JSON" }, { status: 400 });
+  }
+
+  if (!body.body?.trim()) {
+    return Response.json({ error: "Comment body is required" }, { status: 400 });
+  }
+
+  const comment = addComment(Number(id), body.body.trim());
+  if (!comment) {
+    return Response.json({ error: "Alert not found" }, { status: 404 });
+  }
+
+  return Response.json(comment, { status: 201 });
+}