Add AGENTS.md file with project instructions

AGENTS.md

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+# Tschausepp - Jass Card Tracker
+
+## Project Overview
+Mobile-first React web app for tracking Schaffhauser (Jass) card game rounds using camera and feature matching to detect and assign cards to players.
+
+## Tech Stack
+- React 18 (lightweight runtime)
+- TensorFlow.js (lite mode, CDN-hosted, ~5MB)
+- HTML5 Camera API (Mobile-friendly)
+- localStorage (JSON format, max 100 games)
+
+## Key Implementation Details
+
+### Architecture
+- Component-based structure with 5 main screens:
+  1. Setup Screen - Player management and game configuration  
+  2. Camera Screen - Live preview with card detection overlay
+  3. Detection Component - Card boundary detection using image processing
+  4. Assignment Component - Radial sector layout with auto-assignment
+  5. Results Screen - Score calculation and game results
+  6. History Screen - Game storage and export functionality
+
+### Development Commands
+- `npm run dev` - Start development server
+- `npm run build` - Build production version
+- `npm run preview` - Preview production build
+
+### Camera & Detection
+- Uses HTML5 Camera API with environment-facing camera preference
+- Card detection implemented with custom image processing techniques
+- Suit identification (Schellen, Schilten, Eicheln, Rosen) via color analysis
+- Auto-assignment based on radial sector + nearest player calculation
+
+### Data Storage
+- Games stored in localStorage with maximum of 100 games
+- Data structure follows: games → rounds → cards with player assignments
+- JSON format for export functionality
+
+### Mobile-First Design
+- Responsive UI optimized for mobile devices
+- Touch-friendly controls and interfaces
+- Camera access optimized for mobile environment