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>

src/application/index.ts

@@ -0,0 +1,12 @@
+/**
+ * Application Layer
+ *
+ * Use cases and orchestration services.
+ * Coordinates between domain objects and infrastructure.
+ */
+
+export { RelaySelector, createRelaySelector } from './RelaySelector'
+export type { RelaySelectorOptions } from './RelaySelector'
+
+export { PublishingService, publishingService } from './PublishingService'
+export type { DraftEvent, PublishNoteOptions } from './PublishingService'