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/lib/tautulli.ts

@@ -0,0 +1,78 @@
+import { TautulliUser } from "@/lib/types";
+
+interface TautulliRow {
+  friendly_name: string;
+  email: string;
+  plays: number;
+  duration: number;
+  last_seen: number | null;
+}
+
+interface TautulliResponse {
+  response: {
+    result: string;
+    data: {
+      data: TautulliRow[];
+    };
+  };
+}
+
+/**
+ * Returns a Map<lowercaseEmail, TautulliUser>.
+ * Returns null if TAUTULLI_URL/TAUTULLI_API are not set.
+ */
+export async function buildTautulliMap(): Promise<Map<string, TautulliUser> | null> {
+  const url = process.env.TAUTULLI_URL;
+  const key = process.env.TAUTULLI_API;
+
+  if (!url || !key) return null;
+
+  const res = await fetch(
+    `${url}/api/v2?apikey=${key}&cmd=get_users_table&length=1000&order_column=friendly_name&order_dir=asc`,
+    { cache: "no-store" }
+  );
+
+  if (!res.ok) {
+    throw new Error(`Tautulli API error: ${res.status} ${res.statusText}`);
+  }
+
+  const json: TautulliResponse = await res.json();
+
+  if (json.response.result !== "success") {
+    throw new Error(`Tautulli API returned non-success result`);
+  }
+
+  const map = new Map<string, TautulliUser>();
+
+  for (const row of json.response.data.data) {
+    const user: TautulliUser = {
+      friendly_name: row.friendly_name,
+      email: row.email ?? "",
+      plays: row.plays ?? 0,
+      duration: row.duration ?? 0,
+      last_seen: row.last_seen ?? null,
+    };
+
+    if (user.email) {
+      map.set(user.email.toLowerCase(), user);
+    }
+    // Also index by friendly_name as fallback key
+    if (user.friendly_name) {
+      map.set(`name:${user.friendly_name.toLowerCase()}`, user);
+    }
+  }
+
+  return map;
+}
+
+export function lookupTautulliUser(
+  tautulliMap: Map<string, TautulliUser>,
+  email: string,
+  displayName: string
+): TautulliUser | null {
+  return (
+    tautulliMap.get(email.toLowerCase()) ??
+    tautulliMap.get(`name:${displayName.toLowerCase()}`) ??
+    null
+  );
+}