Release GP-SDR 1.2.0: verified Mapper, storage caps, and receiver lab

[DragonKeeperAlex]

Major GP-SDR 1.2.0 feature release.

• Adds strict successfully-identified Mapper records backed by valid decoder frames or nearby RadioReference import evidence.
• Adds location-radius validation so a same-frequency listing in another state is not treated as local.
• Adds identified-only Google Sheet uploads and verification columns in CSV.
• Adds separate Recording/IQ caps, age retention, optional automatic cleanup, and confirmed manual cleanup; profiles, Mapper history, calibration, and channel data are preserved.
• Adds repeated-only/eligibility filters, multi-frequency Discovery and Identify, expanded sorting, live Mapper spectrum/waterfall, and multi-receiver characterization.
• Updates packaging and documentation for v1.2.0.

Validated locally with unit, acceptance, race, vet, JavaScript, universal package, checksum, DMG, signature, simulator package, and concurrent connected HackRF/RTL-SDR capture tests.