Fix license activation and plugin requests ignoring proxy settings (#393)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com

crates/yaak-api/src/error.rs

@@ -0,0 +1,9 @@
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum Error {
+    #[error(transparent)]
+    ReqwestError(#[from] reqwest::Error),
+}
+
+pub type Result<T> = std::result::Result<T, Error>;