chore: initial commit for phase04

apps/daemon/src/auth.rs

@@ -0,0 +1,15 @@
+use tonic::{Request, Status};
+
+/// Validate the daemon token from the gRPC request metadata.
+pub fn check_auth(req: &Request<()>, expected_token: &str) -> Result<(), Status> {
+    let token = req
+        .metadata()
+        .get("authorization")
+        .and_then(|v| v.to_str().ok())
+        .and_then(|v| v.strip_prefix("Bearer "));
+
+    match token {
+        Some(t) if t == expected_token => Ok(()),
+        _ => Err(Status::unauthenticated("Invalid or missing daemon token")),
+    }
+}