fix(storage): harden offline drive fail-fast paths (#2564)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: houseme <4829346+houseme@users.noreply.github.com>

crates/iam/src/lib.rs

@@ -100,7 +100,7 @@ pub async fn init_oidc_sys() -> Result<()> {
         }
         Err(e) => {
             warn!("OIDC initialization failed (non-fatal): {}", e);
-            OidcSys::empty()
+            OidcSys::empty().map_err(Error::StringError)?
         }
     };