Remove 8 redundant mypy settings that are already enabled by strict
mode: warn_redundant_casts, strict_equality, disallow_any_generics,
warn_unused_ignores, disallow_untyped_calls, warn_return_any,
disallow_incomplete_defs, disallow_untyped_defs.
Keep warn_unreachable explicitly since it's not part of strict mode.
Also remove the duplicate exhaustive-match entry from enable_error_code.
Assisted-by: unsloth/Qwen3.6-35B-A3B-GGUF:IQ4_NL and pi.dev 0.81.1
Signed-off-by: Jan Lindemann <jan@janware.com>