New authentication service that delegates OAuth complexity to the Coves
backend. Instead of managing DPoP keys, PKCE, and token exchange client-side,
the backend handles everything and returns sealed tokens.

Key features:
- Browser-based OAuth via flutter_web_auth_2
- Secure token storage per environment (prevents cross-env token reuse)
- Mutex pattern for concurrent token refresh handling
- Handle/DID validation with Bluesky profile URL extraction
- Singleton pattern with test instance creation

The backend's /oauth/mobile/login endpoint handles:
- Handle → DID resolution
- PDS discovery
- PKCE/DPoP key generation
- Token exchange and sealing (AES-256-GCM)

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

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

Simplified session model that works with the Coves backend's sealed token
architecture. The backend handles all OAuth complexity (DPoP, PKCE, token
refresh) and gives us an opaque AES-256-GCM encrypted token.

Key features:
- Parse session from OAuth callback URI (RFC 8252 private-use scheme)
- JSON serialization for secure storage persistence
- Immutable with copyWithToken for refresh operations
- Proper redaction of sensitive data in toString()

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

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

- Add Android productFlavors (dev: social.coves.dev, prod: social.coves)
- Create iOS flavor xcconfig files for future scheme setup
- Update EnvironmentConfig to support flavor-based environment detection
- Add VSCode launch configurations for easy flavor switching
- Update app icon to lil_dude mascot with proper adaptive icon padding

Dev flavor points to local server, prod flavor points to coves.social.
Both apps can be installed side-by-side on the same device.

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

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

- Store timeout timer reference and cancel it in finally block to prevent
stale timer from firing after operation completes
- Check if stream controller is closed before adding cancellation event
to prevent "Cannot add event after closing" error

Add author information to reply screen for consistency with detail view:

- Enable showAuthorFooter in PostCard configuration
- Shows author handle and timestamp above post title
- Provides context about who created the original post
- Maintains same enhanced typography as detail view

This ensures users see clear attribution when composing replies,
matching the enhanced information hierarchy of the detail view.

Changes:
- Set showAuthorFooter: true in PostCard configuration
- Matches detail view settings: 20px title, 16px text, 280px embeds

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

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

Enhance post detail screen with better organization and interaction:

Comment Navigation:
- Wire up dual comment button behavior:
- Input field opens reply composer
- Comment count button scrolls to comments section
- Add _scrollToComments() method with smooth animation
- Uses GlobalKey on CommentsHeader for precise scrolling

Visual Improvements:
- Add 1px border divider before comments section
- Replace blank spacing with clear visual separator
- Matches feed/comment divider styling for consistency
- 16px vertical margins for breathing room

Content Organization:
- Enable author footer in detail view (showAuthorFooter: true)
- Shows author info and timestamp above post title
- Enhanced typography: 20px title, 16px text, 1.6 line height
- Larger embeds (280px) for better content visibility

Changes:
- Add _commentsHeaderKey GlobalKey for scroll targeting
- Add _scrollToComments() method with Scrollable.ensureVisible
- Use onCommentInputTap and onCommentCountTap callbacks
- Add Container divider with AppColors.border
- Enable showAuthorFooter parameter

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

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

Improve post card typography and information hierarchy:

Feed View:
- Increase text opacity from 70% to 85% for better readability
- Maintains visual hierarchy while improving scannability

Detail View:
- Add author info above title (avatar + handle + timestamp)
- Show when post was created (e.g., "2h ago")
- Layout: [Avatar] @username • 2h ago
- Provides clear context about post author and recency

Typography Enhancements:
- Add configurable title font size and weight parameters
- Add configurable text font size, line height, and embed height
- Enable full customization for different view contexts

Changes:
- Add showAuthorFooter parameter to PostCard
- Add _buildAuthorFooter() method with avatar, handle, timestamp
- Add _buildAuthorFallbackAvatar() for missing avatars
- Move author info to appear before title in detail views
- Update text opacity: alpha: 0.7 → 0.85 in feed view

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

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