feat: add experimental Acoustic-1 PHY

[matveyb9]

Summary

• adds the separate experimental Acoustic-1 B-FSK PCM/WAV codec over unchanged ADLP v1 wire objects
• defines a fixed 48 kHz carrier with profile-dependent symbol windows, raw preamble/sync, Hamming(7,4) for length/wire data, bounded frame acquisition and final ADLP CRC-32C validation
• exposes an explicit bootstrap / acoustic1 carrier parameter through the committed flutter_rust_bridge API, Flutter adapter and workbench UI
• adds Acoustic-1 CLI encode/decode commands and a 717,164-byte deterministic golden WAV fixture with SHA-256 documentation and byte-for-byte regression coverage
• adds tests for profiles, bounded leading offset, bounded additive noise, one corrected codeword error, double corruption rejection and wrong-carrier rejection
• updates English-canonical/Russian RFCs, guides, preset reference, roadmap, site status and bilingual documentation CI pairs

Validation

• cargo fmt --all -- --check
• cargo clippy --workspace --all-targets -- -D warnings
• cargo test --workspace
• dart format --output=none --set-exit-if-changed lib test
• flutter analyze
• flutter test
• flutter build web --release
• flutter build linux --debug
• local reproduction of static-site and bilingual document-pair checks

Scope boundary

Acoustic-1 is an experimental controlled PCM/WAV carrier only. It does not establish speaker-to-microphone interoperability or live playback/capture. There is no timing recovery beyond a bounded initial offset, no AGC, interleaving, ARQ, packet segmentation, Bluetooth/radio adapter, authentication or encryption.