UI polish: Illuminated Transcript design language

- Fraunces serif for headings and assistant identity label
- Chat bubbles flipped: assistant responses elevated (card + left indigo
  accent + shadow), user prompts ghosted (transparent bg, muted text)
- AppLogo: book fill changed from text-color to indigo in light mode
- AppHeader: border-bottom removed; active nav uses underline accent
- NoteCard/TaskCard: border replaced with whisper indigo-tint shadow
- HomeView: dashboard-response uses left accent; progress bars indigo;
  empty-state decorative marker; project cards use shadow depth
- NotesListView: btn-new/btn-cta use indigo gradient + glow
- All primary CTA buttons: indigo gradient (135deg #6366f1 → #4f46e5)
  with box-shadow glow on hover
- Dark palette: navy (#1a1a2e family) → slate-indigo (#111113 family)
- Scrollbars: thin 4px indigo-tinted

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/components/ChatMessage.vue

@@ -155,6 +155,12 @@ const timingParts = computed((): string[] => {
 }
 .role-assistant .role-label {
   color: var(--color-primary);
+  font-family: 'Fraunces', Georgia, serif;
+  font-optical-sizing: auto;
+  font-style: italic;
+  font-size: 0.8rem;
+  text-transform: none;
+  letter-spacing: 0;
 }
 
 .thinking-block {