- Add SerializedExtensionError TypeScript bindings from Rust
- Add ExtensionErrorCode enum export with ts-rs
- Create useExtensionError composable with type guards and error message extraction
- Fix developer page toast messages to show proper error messages instead of [object Object]
- Add getErrorMessage helper function for robust error handling across different error types
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Co-Authored-By: Claude <noreply@anthropic.com>
