feat: merge chess_tutor + OpenRouter abstraction

- Merged stefan-kp/chess_tutor into chess-project with full feature set
- Preserved Hermes agent files (agents/, .gitea/, AGENTS.md)
- Added OpenRouter abstraction layer (src/lib/openrouter.ts)
- Created ModelSelector dropdown component with 9 models
- Updated API routes (chat + opening explanation) to use OpenRouter
- Updated useTutorChat to route through OpenRouter API
- Updated onboarding and API key input for OpenRouter
- Created tasks.md with sprint 1 plan
- Updated README with new architecture details

tasks.md

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+# Sprint 1 — Chess Tutor: Local Setup + OpenRouter + Playable Board
+
+**Goal:** Get the chess tutor running locally with a playable board, AI coach via OpenRouter, and model selection.
+
+## Now
+
+- [x] Merge chess_tutor codebase into Tony_tech/chess-project
+- [x] Preserve Hermes agent files (agents/, .gitea/, AGENTS.md)
+- [x] Add OpenRouter abstraction layer (`src/lib/openrouter.ts`)
+- [x] Create model selector dropdown (`src/components/ModelSelector.tsx`)
+- [x] Update API routes to use OpenRouter (chat + opening explanation)
+- [x] Update APIKeyInput for OpenRouter keys
+- [ ] Install dependencies and start dev server
+- [ ] Verify board renders at localhost:3050
+- [ ] Test AI chat with an OpenRouter model
+- [ ] Test AI chat with a different model (switch via dropdown)
+
+## Next
+
+- [ ] Add model selection persistence across sessions
+- [ ] Verify stockfish engine works in browser
+- [ ] Test opening trainer functionality
+- [ ] Test tactical puzzle mode
+- [ ] Add "Chess Coach" personality presets page
+
+## Backlog
+
+- [ ] Add saved game management UI improvements
+- [ ] Add PGN import/export
+- [ ] Add game analysis mode (AI reviews your game)
+- [ ] Multi-language support polish
+- [ ] Performance optimization for mobile
+- [ ] Docker setup for easy deployment
+
+## Setup Notes
+
+```bash
+# 1. Install dependencies
+cd Tony_tech/chess-project
+npm install
+
+# 2. Start dev server (default port 3050)
+npm run dev
+
+# 3. Open browser to http://localhost:3050
+
+# 4. On first visit, the onboarding page will prompt for:
+#    - Language selection
+#    - OpenRouter API key (get one at https://openrouter.ai/keys)
+#    - Model selection (pick your preferred AI model)
+```
+
+### Env Configuration
+
+Create `chess-project/.env.local`:
+```
+OPENROUTER_API_KEY=sk-or-v1-your-key-here
+NEXT_PUBLIC_DEFAULT_MODEL=google/gemini-2.5-flash
+```
+
+If `OPENROUTER_API_KEY` is set as an env var, the opening explanation endpoint uses it automatically. For the tutor chat, users enter their key through the UI (stored in localStorage).
+
+### Available Models
+
+Users can switch between any of these in the model selector dropdown:
+
+| Model | Provider | Cost |
+|-------|----------|------|
+| Gemini 2.5 Flash | Google | Low |
+| Gemini 2.5 Pro | Google | Medium |
+| Claude Sonnet 4 | Anthropic | Medium |
+| Claude 3.5 Haiku | Anthropic | Low |
+| GPT-4o | OpenAI | Medium |
+| GPT-4o Mini | OpenAI | Low |
+| DeepSeek Chat | DeepSeek | Very Low |
+| Grok 3 | xAI | Medium |
+| Llama 3.1 70B | Meta | Low |
+
+### Port
+
+The dev server runs on port **3050** by default (configured in package.json).