feat: update docs

docs/tech-stack.md

@@ -2,39 +2,46 @@
 
 ## Frontend Framework
 - **Next.js 15.4.6**: React-based full-stack framework with App Router
-- **React 19**: Latest React version for component architecture
+- **React 19.1.0**: Latest React version for component architecture
 - **Tailwind CSS 4**: Utility-first CSS framework for styling
 
 ## Street View & Mapping
-- **Mapillary API**: Panoramic street-level imagery provider
-- **PhotoSphere Viewer**: 360° panorama viewer with zoom and fullscreen
-- **Leaflet**: Interactive mapping library
+- **Mapillary API**: Panoramic street-level imagery provider (thumbnail URLs)
+- **Leaflet**: Interactive mapping library for guess placement
 - **OpenStreetMap**: Map tile provider for base maps
+- **@photo-sphere-viewer/core**: 360° panorama viewer (planned integration)
 
 ## Geographic Processing
-- **Nominatim API**: OpenStreetMap geocoding service for city boundaries
-- **Turf.js**: Spatial operations library for point-in-polygon detection and distance calculations
-- **Geospatial Logic**: Server-side coordinate validation and boundary checking
+- **@turf/turf**: Spatial operations library for distance calculations and point processing
+- **Bbox-based Location**: Pre-defined city bounding boxes for location generation
+- **Server-side Calculations**: All geographic processing on backend
 
 ## Data Storage & Session Management
-- **Redis**: Persistent leaderboard storage with automatic trimming
-- **In-Memory Map**: Server-side session storage with 30-minute expiry
-- **Session Isolation**: Secure target coordinate storage per game session
+- **Redis**: Complete session and leaderboard storage
+- **Redis Sorted Sets**: Leaderboard ranking with automatic trimming
+- **UUID v4**: Session identifier generation
+- **30-minute Session Expiry**: Automatic Redis-based cleanup
 
 ## UI Components & Styling
-- **shadcn/ui**: Component library with "new-york" style
+- **shadcn/ui**: Complete component library with "new-york" style
+- **Radix UI**: Headless component primitives
 - **Lucide React**: Icon library
 - **class-variance-authority**: Component variant management
 - **tailwind-merge + clsx**: Dynamic class name handling
-- **CSS Variables**: Theme-based styling system
+
+## Form Handling & Validation
+- **react-hook-form**: Form state management
+- **@hookform/resolvers**: Form validation resolvers
+- **zod**: Schema validation
 
 ## Development & Analytics
 - **ESLint**: Code linting with Next.js configuration
 - **Turbopack**: Development server bundler
-- **Vercel Analytics**: User analytics tracking
-- **Vercel Speed Insights**: Performance monitoring
+- **@vercel/analytics**: User analytics tracking
+- **@vercel/speed-insights**: Performance monitoring
 
 ## Key Dependencies
-- **UUID**: Unique session identifier generation
+- **uuid**: v11.1.0 for unique session identifier generation
+- **redis**: v5.8.0 for data persistence
 - **JavaScript Only**: No TypeScript - pure JavaScript implementation
 - **Individual Parameters**: Functions use separate parameters instead of object destructuring