Zero SDR v0.1.0-rc.2

Second Cardputer Zero hardware-validation candidate. This build adds graceful audio-only degradation: live RF and spectrum continue when ALSA cannot open or suffers an unrecoverable write failure, while the radio and settings screens show a localized NO AUDIO state.

Validation passed: 9 host tests including startup/runtime audio failures, 50 locale and audio-state screenshots, 5 deterministic receiver states, TrueType/glyf font validation, Store asset validation, and ARM64 package inspection.

This remains a pre-release. Physical Cardputer Zero RF/audio, USB power and permissions, thermals, and sustained performance must pass issue #1 before App Store submission.