docs: add README and project gitignore

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

.gitignore

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+# Rust
+backend/target/
+
+# Node / Vite
+frontend/node_modules/
+frontend/dist/
+
+# E2E
+e2e/node_modules/
+
+# Misc
+*.log
+.DS_Store

README.md

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+## curltastic
+
+A 1v1 async multiplayer 2D curling game for mobile browser.
+
+- **Backend** — Rust, Axum, WebSocket, Rapier2D physics (server-authoritative, 120 Hz).
+- **Frontend** — TypeScript, Vite, Canvas2D, portrait-first touch UI.
+
+### Run locally
+
+1. Install Rust via [rustup](https://rustup.rs/) (if not already installed).
+2. Start the backend:
+   ```bash
+   cd backend
+   cargo run --release
+   # listens on 0.0.0.0:3000
+   ```
+3. Start the frontend dev server:
+   ```bash
+   cd frontend
+   npm install
+   npm run dev
+   # opens on 0.0.0.0:5173 by default
+   ```
+4. Open two browser tabs to the same room URL, e.g.:
+   ```
+   http://localhost:5173/?room=DEMO1
+   ```
+   The first tab waits; the second starts the match. Use the *Copy share link* button to invite an opponent.
+
+### Mobile devices
+
+The frontend binds to `0.0.0.0` via `--host`. Find your machine's LAN IP and open `http://<ip>:5173/?room=CODE` on the phone. Both devices must be on the same Wi-Fi and able to reach the backend on port `3000`.
+
+### Controls
+
+- Drag inside the house to place the broom (aim point).
+- Tap a weight `1`–`10`.
+- Tap **THROW**.
+- The server runs the physics and streams the trajectory; the frontend interpolates the animation.
+
+### Architecture
+
+- WebSocket JSON protocol with tagged messages.
+- Server simulates each throw at 120 Hz and sends a subset of `(x, y, t)` path points at 40 Hz.
+- All game state, scoring, end management, and hammer rules live on the server.
+- Disconnects are tolerated: the room and turn remain in memory.
+
+### E2E tests
+
+With the backend and frontend dev server running:
+
+```bash
+cd e2e
+npm install -g ws   # or npm install ws locally in the project
+node e2e_test.cjs   # room lifecycle, throw, trajectory, out-of-play removal
+node e2e_score.cjs  # stones remain in play and alternate turns
+```
+
+### Limitations / known simplifications
+
+- No accounts, persistence, anti-cheat, replay log, or turn timer.
+- Curl is fixed as a function of release speed (more curl at lower speed); sweeping is not implemented.
+- Stones that pass the back line or leave the sheet are removed from play.