UX/UI/perf pass: admin tabs, theme toggle, log polish, mod search, JAR cache

- Admin page split into tabs (Server/Players/Chat/Mods/Backups/Logs) with
  hash + localStorage persistence; inactive tabs no longer mount.
- Log viewer: level color-coding, search, level filter chips, auto-scroll
  toggle, copy button, visible-line count.
- Installed mods list: search field + side filter (all/both/server/client)
  with live count; public ModList gets skeleton + empty states and search.
- Theme toggle with no-flash inline init, localStorage + system preference.
- Layout: full OG / Twitter metadata, title template, keywords,
  dual-theme themeColor, metadataBase.
- lib/mods.ts: per-jar mtime+size parse cache (cold 6s -> warm ~45ms on
  /api/mods for the full mod list); cache eviction on mod removal.
- ChatBridge polling eased 3s -> 5s with 2s stale window.

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

lib/mods.ts

@@ -81,12 +81,18 @@ function extractToml(content: string, key: string): string | null {
   return match ? match[1] : null;
 }
 
-function extractModMeta(
+type JarParseCacheEntry = {
+  mtimeMs: number;
+  size: number;
+  meta: Omit<ModMeta, "side">;
+};
+
+const jarParseCache = new Map<string, JarParseCacheEntry>();
+
+function parseJarMeta(
   dir: string,
   filename: string
 ): Omit<ModMeta, "side"> {
-  const filePath = join(dir, filename);
-  const stat = statSync(filePath);
   let modId = "unknown";
   let displayName = filename
     .replace(/-(\d)/, " $1")
@@ -95,7 +101,7 @@ function extractModMeta(
   let version = "";
 
   try {
-    const zip = new AdmZip(filePath);
+    const zip = new AdmZip(join(dir, filename));
     const toml = zip.getEntry("META-INF/mods.toml");
     if (toml) {
       const content = toml.getData().toString("utf8");
@@ -112,10 +118,33 @@ function extractModMeta(
     displayName,
     version,
     filename,
-    size: (stat.size / 1024 / 1024).toFixed(1) + " MB",
+    size: "",
   };
 }
 
+function extractModMeta(
+  dir: string,
+  filename: string
+): Omit<ModMeta, "side"> {
+  const filePath = join(dir, filename);
+  const stat = statSync(filePath);
+  const cacheKey = filePath;
+  const cached = jarParseCache.get(cacheKey);
+
+  if (cached && cached.mtimeMs === stat.mtimeMs && cached.size === stat.size) {
+    return { ...cached.meta, size: (stat.size / 1024 / 1024).toFixed(1) + " MB" };
+  }
+
+  const meta = parseJarMeta(dir, filename);
+  jarParseCache.set(cacheKey, {
+    mtimeMs: stat.mtimeMs,
+    size: stat.size,
+    meta,
+  });
+
+  return { ...meta, size: (stat.size / 1024 / 1024).toFixed(1) + " MB" };
+}
+
 export function getModDetails(): ModMeta[] {
   return memo(MODS_CACHE_KEY, MODS_CACHE_TTL, computeModDetails);
 }
@@ -155,8 +184,10 @@ export function removeMod(filename: string): void {
 
   if (existsSync(serverPath)) {
     unlinkSync(serverPath);
+    jarParseCache.delete(serverPath);
   } else if (existsSync(clientPath)) {
     unlinkSync(clientPath);
+    jarParseCache.delete(clientPath);
   } else {
     throw new Error(`Mod "${filename}" not found`);
   }