Introduce a static inline `wrenHasError` function in `wren_value.h` that encapsulates the `!IS_NULL(fiber->error)` pattern, improving code readability and maintainability. Replace all direct `IS_NULL(fiber->error)` checks across `wren_core.c`, `wren_vm.c`, and the interpreter loop with calls to this new helper. Additionally, clean up commented-out debug print statements and extraneous blank lines in the `trim` methods within the embedded core module source string, and add Michel Hermier to the AUTHORS file.