Fix/warn credential permission failures

.changeset/fix-credential-permission-warnings.md

@@ -0,0 +1,10 @@
+---
+"@googleworkspace/cli": patch
+---
+
+fix: warn on credential file permission failures instead of ignoring
+
+Replaced silent `let _ =` on `set_permissions` calls in `save_encrypted`
+with `eprintln!` warnings so users are aware if their credential files
+end up with insecure permissions. Also log keyring access failures
+instead of silently falling through to file storage.

src/credential_store.rs

@@ -119,7 +119,9 @@ fn get_or_create_key() -> anyhow::Result<[u8; 32]> {
 
                 return Ok(cache_key(key));
             }
-            Err(_) => {} // Fallthrough to file storage
+            Err(e) => {
+                eprintln!("Warning: keyring access failed, falling back to file storage: {e}");
+            }
         }
     }