feat: expand video/audio format options to all system-available formats

[sfegette]

Summary

Currently radcap offers a fixed list of video/audio format options. This should be expanded to dynamically surface all formats natively available on the current system via AVFoundation, for both video and audio outputs.

Desired behavior

• Query AVFoundation at runtime for available codecs/containers (e.g. AVOutputSettingsAssistant, AVFileType, available AVVideoCodecType values)
• Populate format pickers from that list rather than a hardcoded set
• Both video format and audio format selectors should reflect what the system can actually encode — no options that would silently fail or require external tools
• Gracefully handle cases where a previously-saved preference is no longer available on the current system

Notes

• Prefer native AVFoundation types; no FFmpeg or third-party encoder dependency
• Consider grouping or ordering formats by quality/common-use (ProRes, HEVC, H.264, etc.) if the list gets long