feat: add Settings and Suite pages with comprehensive settings management and question suite builder

- Implemented SettingsPage for configuring default provider, temperature, and model paths.
- Added SuitePage for managing a suite of questions with features to add, edit, duplicate, and delete questions.
- Introduced TypeScript configuration files for app and node environments.
- Set up Vite configuration for development server with API proxying to backend.

web/src/lib/format.ts

@@ -0,0 +1,52 @@
+/** Small display helpers shared across views. */
+
+export function formatDuration(seconds: number): string {
+  if (!Number.isFinite(seconds) || seconds < 0) return '—'
+  if (seconds < 1) return `${Math.round(seconds * 1000)}ms`
+  if (seconds < 60) return `${seconds.toFixed(1)}s`
+  const minutes = Math.floor(seconds / 60)
+  const rest = Math.round(seconds % 60)
+  if (minutes < 60) return `${minutes}m ${rest}s`
+  return `${Math.floor(minutes / 60)}h ${minutes % 60}m`
+}
+
+export function formatBytes(bytes: number): string {
+  if (bytes < 1024) return `${bytes} B`
+  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`
+  return `${(bytes / (1024 * 1024)).toFixed(1)} MB`
+}
+
+export function formatRelativeTime(epochSeconds: number): string {
+  const delta = Date.now() / 1000 - epochSeconds
+  if (delta < 60) return 'just now'
+  if (delta < 3600) return `${Math.floor(delta / 60)}m ago`
+  if (delta < 86400) return `${Math.floor(delta / 3600)}h ago`
+  if (delta < 604800) return `${Math.floor(delta / 86400)}d ago`
+  return new Date(epochSeconds * 1000).toLocaleDateString()
+}
+
+export function formatTimestamp(epochSeconds: number): string {
+  return new Date(epochSeconds * 1000).toLocaleString(undefined, {
+    month: 'short',
+    day: 'numeric',
+    hour: '2-digit',
+    minute: '2-digit',
+  })
+}
+
+export function clockTime(epochMs: number = Date.now()): string {
+  return new Date(epochMs).toLocaleTimeString(undefined, { hour12: false })
+}
+
+/** Title shown for a question — the engine uses the first non-empty line. */
+export function deriveTitle(prompt: string, fallback = 'Untitled question'): string {
+  for (const line of prompt.split('\n')) {
+    const trimmed = line.trim()
+    if (trimmed) return trimmed
+  }
+  return fallback
+}
+
+export function cx(...values: (string | false | null | undefined)[]): string {
+  return values.filter(Boolean).join(' ')
+}