[Release] Prepare v1.11.1 stable

[Regstar2]

Summary

Prepares stable v1.11.1.

• bumps Android metadata to versionName 1.11.1 / versionCode 57;
• updates release audit and CI preflight;
• adds RU/EN release notes and curated GitHub Release notes;
• updates README, CHANGELOG, release workflow docs and checklist;
• documents the new opt-in boot autostart behavior and Xiaomi/HyperOS OEM permission caveat.

versionCode 57 intentionally stays above the signed device-smoke build that used code 56, so the official release can upgrade that installation normally.

Validation

• PR CI must pass before merge.
• Boot autostart was verified on a physical Xiaomi/HyperOS device after enabling the OEM background/autostart permission.
• Release workflow will rebuild from the exact tag, verify package/version metadata and signature, and publish APK + SHA-256.

Refs #95
Refs #96