Performance: RCON pooling, route caching, parallel status probe

Server:
- lib/cache.ts: tiny TTL memo for hot paths.
- lib/rcon.ts: pooled connection with 30s idle close and one-shot retry;
  was opening a fresh TCP per RCON call.
- /api/status: race protocol-ping + RCON with Promise.any (was sequential
  with 5s timeouts) and memo 3s; adds Cache-Control.
- /api/players: memo 10s, invalidated on mutations.
- /api/mods: getModDetails memo 10s (invalidated on install/remove) —
  eliminates per-request readdirSync/statSync/AdmZip parse.
- /api/analytics: reverse-scan JSONL to window cutoff (O(window) vs O(file))
  and memo 30s.
- /api/logs: memo 2s to throttle journalctl spawns during Live mode.

Client:
- StatusCard + ServerControls: staleTime 5s, both poll every 10s, dedup
  via shared query key.
- Analytics: staleTime 30s; memoize sparkline SVG paths.
- Modrinth search icons + mc-heads avatars: width/height + loading=lazy +
  decoding=async.
- next.config.ts: images.remotePatterns for future next/image migration,
  explicit compress=true.

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

lib/mods.ts

@@ -18,8 +18,16 @@ import {
   MC_SERVER_PORT,
 } from "./constants";
 import { sendCommand } from "./rcon";
+import { memo, invalidate } from "./cache";
 import type { ModSide } from "./modrinth";
 
+const MODS_CACHE_KEY = "mods:details";
+const MODS_CACHE_TTL = 10_000;
+
+export function invalidateModsCache(): void {
+  invalidate("mods:");
+}
+
 const MODPACK_ZIP = "/var/www/minecraft/modpack.zip";
 const MODPACK_MODS = "/var/www/minecraft/mods";
 
@@ -56,6 +64,7 @@ export function addModMetadata(
   const metadata = loadModMetadata();
   metadata[filename] = entry;
   saveModMetadata(metadata);
+  invalidateModsCache();
 }
 
 export function removeModMetadata(filename: string): void {
@@ -108,6 +117,10 @@ function extractModMeta(
 }
 
 export function getModDetails(): ModMeta[] {
+  return memo(MODS_CACHE_KEY, MODS_CACHE_TTL, computeModDetails);
+}
+
+function computeModDetails(): ModMeta[] {
   const metadata = loadModMetadata();
 
   // Server mods
@@ -149,6 +162,7 @@ export function removeMod(filename: string): void {
   }
 
   removeModMetadata(filename);
+  invalidateModsCache();
 }
 
 export function isClientOnlyMod(filename: string): boolean {