Adds coverage.excluded_adapters: adapters listed here ignore the universal
coverage bbox and use their own config (the "advanced override", native
only). _coverage_for() returns None for excluded adapters; satpass seeding
respects it too. Backend for the GUI override toggles.
Co-authored-by: Matt Johnson <mj@k7zvx.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>