refactor: isolate auth layout, unify tags, add editor animation and pin indicator

- Create (auth) and (app) layout groups to isolate login/setup pages
  from the main app chrome (header, sidebar, footer)
- Use window.location.href instead of goto() after login/setup to
  ensure clean full-page load across layout groups
- Add reusable TagChip component, used in TagFilter and NoteCard
- Add fade-in/pop-in entrance animation to note editor overlay
- Add persistent clickable pin indicator on pinned cards (top-right
  bookmark icon, replaces hover-only pin button for pinned notes)
- Improve "Add a crumb..." button with + icon and dashed border
- Update CLAUDE.md with retro parchment design system guidelines
- Add /.claude/ to .gitignore

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

CLAUDE.md

@@ -14,21 +14,73 @@ Crumbs by Bretzel — self-hostable note-taking app. Single-user, offline-first
 - **PWA**: `@vite-pwa/sveltekit` for service worker and offline caching
 - **Package manager**: pnpm
 
+## Design system: Retro Parchment
+
+The UI follows a **parchment + 8-bit retro** aesthetic. All design decisions must preserve this character.
+
+### Color palette
+
+All colors are CSS variables in `src/app.css`. Never use hardcoded Tailwind colors (e.g. `text-gray-500`, `bg-red-600`) — always reference CSS variables:
+
+| Variable | Value | Usage |
+|---|---|---|
+| `--bg-base` | `#f0e6d3` | Page background (warm parchment) |
+| `--bg-surface` | `#faf5eb` | Cards, panels, inputs |
+| `--primary` | `#C8860A` | Brand gold — links, active states, accents |
+| `--primary-hover` | `#E8A020` | Gold hover state |
+| `--text` | `#1a1a2e` | Primary text (near-black) |
+| `--text-muted` | `#6b6272` | Secondary text, placeholders |
+| `--border` | `#1a1a2e` | Strong borders (editor, login card) |
+| `--border-subtle` | `#d4cabb` | Default card borders, dividers |
+| `--destructive` | `#a63d2f` | Delete actions, error icons |
+| `--error-bg/border/text` | warm reds | Error states (themed, not clinical red) |
+| `--success-bg/text` | warm greens | Success states |
+| `--card-shadow` | `2px 2px 0px` | Hard-offset retro shadow (no blur) |
+| `--card-shadow-hover` | `3px 3px 0px` | Hover shadow in primary gold |
+
+Note colors for cards are defined in `src/lib/utils/colors.ts`.
+
+### Typography
+
+- **Body**: `JetBrains Mono` (monospace) — the hacker/dev aesthetic
+- **Brand / empty states**: `Press Start 2P` (pixel font) — the 8-bit accent
+- These two fonts are intentional. Do not replace them or add others.
+
+### Visual rules
+
+- **Shadows**: Always hard-offset (`2px 2px 0px`) with zero blur. Never use `shadow-sm`, `shadow-md` etc. — they look too modern.
+- **Corners**: `rounded-sm` everywhere. Sharp, not rounded. Exception: color picker circles use `rounded-full`.
+- **Borders**: Default card borders use `--border-subtle`. `--border` is for strong emphasis (editor, login card). Hover borders use `--primary`.
+- **Animations**: Crisp and fast (150ms `ease-out`). No spring physics, no bounce. The retro feel comes from snappy transitions.
+- **Background texture**: A subtle 4px pixel grid overlay at 3% opacity (defined in `body::before`).
+- **Checkboxes**: Use `accent-color: var(--primary)` globally — gold checkboxes match the theme.
+- **Icons**: Lucide icons throughout. Keep at 16-20px size.
+
+### Layout groups
+
+- `(auth)` — Login/setup pages: minimal centered layout, no app chrome
+- `(app)` — Main app: header, sidebar, footer, toast notifications
+
 ## Project structure
 
 ```
 src/
-  routes/              # SvelteKit pages and API routes
-    +page.svelte       # Main notes view
-    login/             # Login page
-    setup/             # First-time password setup
+  routes/
+    +layout.svelte     # Root layout (imports CSS only)
+    (auth)/            # Layout group: login/setup (minimal, no app chrome)
+      +layout.svelte   # Centered parchment background
+      login/           # Login page
+      setup/           # First-time password setup
+    (app)/             # Layout group: main app (header, sidebar, footer)
+      +layout.svelte   # App shell with Header, Sidebar, Toast
+      +page.svelte     # Main notes view
     api/auth/          # Login, logout, setup endpoints
     api/notes/         # CRUD + attachments
     api/search/        # Full-text search
     api/sync/          # Offline sync
     api/tags/          # Tag management
   lib/
-    components/        # Svelte components (NoteCard, NoteEditor, ColorPicker, etc.)
+    components/        # Svelte components (NoteCard, NoteEditor, TagChip, etc.)
     stores/            # Svelte stores (notes.ts, theme.ts)
     server/db/         # Drizzle schema + connection (schema.ts, index.ts)
     server/            # Auth logic, attachment handling