feat(server): load .env via dotenvy on startup

The binary now reads a .env file itself (dotenvy::dotenv() at the top of main),
so 'cargo run -p server' / the release binary pick up config without relying on
just's 'set dotenv-load'. Missing .env is a no-op.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

crates/server/src/main.rs

@@ -41,6 +41,10 @@ impl From<RoleArg> for Role {
 
 #[tokio::main]
 async fn main() -> anyhow::Result<()> {
+    // Load a .env file (if present) so the binary picks up config when run directly,
+    // not only via `just` (which uses `set dotenv-load`). A missing .env is fine.
+    dotenvy::dotenv().ok();
+
     tracing_subscriber::fmt()
         .with_env_filter(tracing_subscriber::EnvFilter::from_default_env())
         .init();