Build music-quiz installer and management site per spec

Implements the full spec described in README.md:

Management site (Node + TypeScript + Express + EJS):
- Public main page lists packs registered in manifest.json.
- /op login (account.json, internal-only), /op/dashboard manages packs
  with horizontal-scroll cards, add/select-and-delete flow, and the
  /op/dashboard/:packName editor (Mojang release dropdown, dynamic
  mods/resourcepacks lists, platform/RAM fields, file rename).
- Routes for /manifest.json (public) and /file/* (server pack files).
- Middleware blocks /account.json and /manifest/* directory access.

Installer (Electron):
- Five page renderer driven by IPC (preload contextBridge API):
  pack pick → single/multi → server install (path no-Korean check, JDK
  detect, file download, EULA, RAM gating, local web config editor,
  UPnP/port-forward check) → client install (.mc_custom mods +
  resourcepacks + launcher_profiles.json gameDir/javaArgs) → finish
  toggles (server folder, shortcut, server start, launcher start).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

installer/styles.css

@@ -0,0 +1,162 @@
+:root {
+  color-scheme: dark;
+  --bg: #0d1117;
+  --bg-alt: #161b22;
+  --bg-card: #1f242c;
+  --border: #30363d;
+  --text: #e6edf3;
+  --text-muted: #8b949e;
+  --accent: #2f81f7;
+  --danger: #f85149;
+  --success: #3fb950;
+}
+
+* { box-sizing: border-box; }
+
+html, body {
+  margin: 0;
+  padding: 0;
+  background: var(--bg);
+  color: var(--text);
+  font-family: 'Pretendard', -apple-system, 'Segoe UI', sans-serif;
+  height: 100vh;
+}
+
+body {
+  display: grid;
+  grid-template-rows: auto 1fr;
+  grid-template-columns: 1fr;
+}
+
+.appHeader {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  padding: 16px 24px;
+  background: var(--bg-alt);
+  border-bottom: 1px solid var(--border);
+}
+
+.appHeader h1 { margin: 0; font-size: 18px; }
+
+.stepIndicator {
+  display: flex;
+  gap: 8px;
+  margin: 0;
+  padding: 0;
+  list-style: none;
+  font-size: 12px;
+}
+
+.stepIndicator li {
+  padding: 6px 12px;
+  border: 1px solid var(--border);
+  border-radius: 999px;
+  color: var(--text-muted);
+}
+
+.stepIndicator li.active {
+  border-color: var(--accent);
+  color: var(--text);
+  background: rgba(47, 129, 247, 0.15);
+}
+
+.stepIndicator li.done {
+  border-color: var(--success);
+  color: var(--success);
+}
+
+main {
+  padding: 28px 32px 100px;
+  overflow-y: auto;
+}
+
+.page { max-width: 720px; margin: 0 auto; }
+
+.page h2 { margin: 0 0 16px; }
+
+.page p { color: var(--text-muted); }
+
+.cardChoice {
+  display: grid;
+  gap: 12px;
+  margin: 24px 0;
+}
+
+.cardChoice button {
+  background: var(--bg-card);
+  border: 1px solid var(--border);
+  color: var(--text);
+  padding: 16px 18px;
+  border-radius: 12px;
+  text-align: left;
+  cursor: pointer;
+  font: inherit;
+}
+
+.cardChoice button:hover { border-color: var(--accent); }
+.cardChoice button.selected { border-color: var(--accent); background: rgba(47, 129, 247, 0.15); }
+
+.actionRow {
+  display: flex;
+  justify-content: space-between;
+  margin-top: 24px;
+  gap: 12px;
+  flex-wrap: wrap;
+}
+
+.primaryBtn,
+.secondaryBtn,
+.dangerBtn {
+  font: inherit;
+  padding: 10px 18px;
+  border-radius: 8px;
+  cursor: pointer;
+  border: 1px solid transparent;
+}
+
+.primaryBtn { background: var(--accent); color: white; }
+.primaryBtn:disabled { background: #2c3849; cursor: not-allowed; }
+
+.secondaryBtn { background: var(--bg-card); border-color: var(--border); color: var(--text); }
+.secondaryBtn:hover { border-color: var(--accent); }
+
+.dangerBtn { background: var(--danger); color: white; }
+
+.fieldset { display: flex; flex-direction: column; gap: 8px; margin: 16px 0; }
+.fieldset label { display: flex; gap: 8px; align-items: center; }
+.fieldset input[type="text"], .fieldset input[type="url"] { flex: 1; background: var(--bg); color: var(--text); border: 1px solid var(--border); padding: 8px 10px; border-radius: 6px; }
+
+.formMessage { font-size: 13px; color: var(--text-muted); margin-top: 6px; }
+.formMessage.error { color: var(--danger); }
+.formMessage.success { color: var(--success); }
+
+.subStep { padding: 14px 16px; border: 1px solid var(--border); border-radius: 12px; margin-bottom: 12px; background: var(--bg-card); }
+.subStep h3 { margin: 0 0 8px; font-size: 16px; }
+
+.logViewer {
+  position: fixed;
+  bottom: 0;
+  left: 0;
+  right: 0;
+  height: 200px;
+  background: #0a0d11;
+  border-top: 1px solid var(--border);
+  display: grid;
+  grid-template-rows: auto 1fr;
+}
+
+.logViewer header { display: flex; justify-content: space-between; align-items: center; padding: 6px 12px; background: var(--bg-alt); }
+.logViewer header h2 { margin: 0; font-size: 13px; }
+.logViewer header button { background: transparent; border: 1px solid var(--border); color: var(--text); border-radius: 6px; padding: 4px 8px; cursor: pointer; }
+.logViewer pre { margin: 0; padding: 8px 12px; overflow-y: auto; font-family: 'Consolas', monospace; font-size: 12px; }
+
+.eulaBox { background: var(--bg-card); border: 1px solid var(--border); padding: 16px; border-radius: 10px; max-height: 200px; overflow-y: auto; font-size: 12px; line-height: 1.6; }
+
+.toggleRow { display: flex; align-items: center; gap: 10px; margin: 8px 0; }
+
+.statusBadge { display: inline-flex; padding: 3px 10px; border-radius: 999px; font-size: 12px; }
+.statusBadge.pending { background: #2c3849; color: var(--text-muted); }
+.statusBadge.ok { background: rgba(63, 185, 80, 0.2); color: var(--success); }
+.statusBadge.warn { background: rgba(248, 197, 49, 0.2); color: #f0c244; }
+.statusBadge.fail { background: rgba(248, 81, 73, 0.2); color: var(--danger); }