Per-player playtime tracking + sparkline hover tooltips

- New GET /api/players/playtime (authed): reads each vanilla stats file
  under /home/minecraft/server/world/stats and maps uuid→name via
  usercache.json. Returns playtime in ticks and hours, plus file mtime
  as "last seen". Memoized 60s via lib/cache#memoAsync.
- New PlaytimeLeaderboard card in the Players tab:
    - Rank, avatar (click → PlayerDrawer), relative last-seen, hours.
    - Top 10 by default with toggle to show all; combined hours badge.
- PlayerDrawer surfaces the player's total hours + last-seen using the
  same cached playtime query, plus fills in UUID if the player is not
  in ops/whitelist/banned.
- lib/time.ts: formatHours() — minutes under 1h, "H.Hh" under a day,
  "Dd Hh" above.
- Analytics sparklines gain hover/touch tooltips:
    - Timestamps threaded through from each MetricEntry.
    - SVG overlay captures onMouseMove/onTouchMove, computes nearest
      index by x, draws a dashed guide line + focus dot.
    - Floating tooltip shows HH:MM + formatted value with unit; edge
      clamping keeps it in-frame at the extremes.
    - Per-chart formatValue so RAM shows GB, CPU 0 decimals, Players
      integer, TPS 1 decimal. Keeps the peak-player marker intact.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/api/players/playtime/route.ts

@@ -0,0 +1,88 @@
+import { NextResponse } from "next/server";
+import { readdirSync, readFileSync, statSync } from "fs";
+import { join } from "path";
+import { auth } from "@/lib/auth";
+import { memoAsync } from "@/lib/cache";
+
+export const dynamic = "force-dynamic";
+export const runtime = "nodejs";
+
+const STATS_DIR = "/home/minecraft/server/world/stats";
+const USERCACHE = "/home/minecraft/server/usercache.json";
+const TICKS_PER_HOUR = 20 * 60 * 60;
+
+type Entry = {
+  uuid: string;
+  name: string;
+  playtimeTicks: number;
+  playtimeHours: number;
+  lastPlayedMs: number;
+};
+
+type UserCacheEntry = { name: string; uuid: string };
+
+function loadNameMap(): Map<string, string> {
+  try {
+    const arr = JSON.parse(readFileSync(USERCACHE, "utf8")) as UserCacheEntry[];
+    return new Map(arr.map((e) => [e.uuid, e.name]));
+  } catch {
+    return new Map();
+  }
+}
+
+function computePlaytime(): Entry[] {
+  const names = loadNameMap();
+  let files: string[];
+  try {
+    files = readdirSync(STATS_DIR).filter((f) => f.endsWith(".json"));
+  } catch {
+    return [];
+  }
+
+  const out: Entry[] = [];
+  for (const f of files) {
+    const uuid = f.replace(/\.json$/, "");
+    const path = join(STATS_DIR, f);
+    try {
+      const data = JSON.parse(readFileSync(path, "utf8")) as {
+        stats?: { "minecraft:custom"?: Record<string, number> };
+      };
+      const ticks = Number(
+        data.stats?.["minecraft:custom"]?.["minecraft:play_time"] || 0
+      );
+      const mtime = statSync(path).mtimeMs;
+      out.push({
+        uuid,
+        name: names.get(uuid) || uuid.slice(0, 8),
+        playtimeTicks: ticks,
+        playtimeHours: Math.round((ticks / TICKS_PER_HOUR) * 100) / 100,
+        lastPlayedMs: mtime,
+      });
+    } catch {
+      // Skip unreadable/corrupt stat files
+    }
+  }
+  out.sort((a, b) => b.playtimeTicks - a.playtimeTicks);
+  return out;
+}
+
+export async function GET() {
+  const session = await auth();
+  if (!session) {
+    return NextResponse.json({ error: "Unauthorized" }, { status: 403 });
+  }
+
+  try {
+    const data = await memoAsync("players:playtime", 60_000, async () =>
+      computePlaytime()
+    );
+    return NextResponse.json(data, {
+      headers: { "Cache-Control": "private, max-age=60" },
+    });
+  } catch (e) {
+    return NextResponse.json(
+      { error: (e as Error).message },
+      { status: 500 }
+    );
+  }
+}