feat: add device acceptance protocol

[matveyb9]

Summary

• adds an English-canonical/Russian device-acceptance protocol for future live audio adapter evidence
• defines report classes, device/route metadata, privacy-safe recording availability states and supported-route decision gates
• adds a narrow v1 JSON Schema, a zero-dependency Node validator, valid unexecuted template fixture and intentionally invalid fixtures
• adds deterministic validator tests to documentation CI
• expands the device-compatibility issue form with reproducible revision/fixture/settings/outcome fields while prohibiting personal content and identifying information
• updates documentation navigation, roadmap and public status without claiming a physical route, device observation or supported device

Validation

• node --check tools/device-acceptance/validate-report.mjs
• node --check tools/device-acceptance/test-validator.mjs
• validator run on the unexecuted template and deterministic valid/invalid fixture tests
• JSON parse of schema and fixtures
• cargo fmt --all -- --check
• cargo clippy --workspace --all-targets -- -D warnings
• cargo test --workspace
• Dart format, flutter analyze, flutter test, flutter build web --release, flutter build linux --debug
• static-site and bilingual documentation validation

Scope boundary

This PR prepares reporting and review infrastructure only. It contains no real device measurement, raw recording, live audio adapter, BER/SNR/range metric, device compatibility result or support claim. The committed report fixture is explicitly unexecuted.