feat: add QR scanner, improve UX, and simplify navigation

- Add live camera QR scanner for nsec/ncryptsec login
- Replace browser prompt() with proper password dialog for ncryptsec
- Add missing /notes/:id route for thread view navigation
- Remove explore section entirely (button, page, routes)
- Remove profile button from bottom nav, avatar now opens profile
- Remove "Notes" tab from feed, default to showing all posts/replies
- Add PasswordPromptProvider for secure password input
- Add SidebarDrawer for mobile navigation
- Add domain layer with value objects and adapters
- Various UI and navigation improvements

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tailwind.config.js

@@ -3,6 +3,9 @@ export default {
   darkMode: ['class'],
   content: ['./index.html', './src/**/*.{ts,tsx}'],
   theme: {
+    fontFamily: {
+      sans: ['"Noto Sans"', '"Noto Color Emoji"', 'ui-sans-serif', 'system-ui', 'sans-serif']
+    },
     extend: {
       borderRadius: {
         lg: 'var(--radius)',
@@ -12,6 +15,9 @@ export default {
         '2xl': 'calc(var(--radius) + 8px)'
       },
       colors: {
+        chrome: {
+          background: 'hsl(var(--chrome-background))'
+        },
         surface: {
           background: 'hsl(var(--surface-background))'
         },