refactor: purge Node.js, Rust is the one true backend

- Moved boosapi-rs/* to repo root
- Deleted all Node.js source (src/server/, src/web/, scripts/)
- Deleted node_modules, package.json, tsconfig, vite.config
- Updated .gitignore and AGENTS.md for Rust-only stack
- Fixed static file path for frontend dist/web/
- Dockerfile stays the same (already Rust-only)
- Kept dist/web/ for Rust static serving

src/main.rs

@@ -0,0 +1,70 @@
+use axum::serve;
+use boosapi::{config::AppConfig, db, AppState};
+use std::net::SocketAddr;
+use tokio::signal;
+use tracing_subscriber::EnvFilter;
+
+#[tokio::main]
+async fn main() -> anyhow::Result<()> {
+    // Initialize tracing
+    tracing_subscriber::fmt()
+        .with_env_filter(EnvFilter::from_default_env())
+        .init();
+
+    // Load config
+    let config = AppConfig::load()?;
+    tracing::info!("Loaded configuration");
+
+    // Create database pool
+    let pool = db::create_pool(&config.db.url, config.db.max_connections).await?;
+    tracing::info!("Database connected");
+
+    // Run migrations
+    sqlx::migrate!("./migrations").run(&pool).await?;
+    tracing::info!("Database migrations applied");
+
+    // Build app state
+    let state = AppState::new(config.clone(), pool);
+
+    // Build router
+    let app = boosapi::routes::build_router(state);
+
+    // Start server
+    let addr = SocketAddr::new(config.server.host.parse()?, config.server.port);
+    tracing::info!("Starting server on {addr}");
+
+    serve(
+        tokio::net::TcpListener::bind(addr).await?,
+        app.into_make_service(),
+    )
+    .with_graceful_shutdown(shutdown_signal())
+    .await?;
+
+    Ok(())
+}
+
+async fn shutdown_signal() {
+    let ctrl_c = async {
+        signal::ctrl_c()
+            .await
+            .expect("failed to install Ctrl+C handler");
+    };
+
+    #[cfg(unix)]
+    let terminate = async {
+        signal::unix::signal(signal::unix::SignalKind::terminate())
+            .expect("failed to install SIGTERM handler")
+            .recv()
+            .await;
+    };
+
+    #[cfg(not(unix))]
+    let terminate = std::future::pending::<()>();
+
+    tokio::select! {
+        _ = ctrl_c => {},
+        _ = terminate => {},
+    }
+
+    tracing::info!("Shutdown signal received, starting graceful shutdown");
+}