Simplify the 2.0.0a2 release

[shigabeev]

What changed

• reduce the repository from 100 tracked files to about 40
• remove 19,624 lines of legacy service code, duplicate reports, release scaffolding, and planning documents
• keep the parser, message address detection, compact model, focused tests, and reproducible benchmark
• make the Russian README primary and keep a concise English translation
• consolidate aggregate metrics into one benchmark document and retain the detailed 500-case result table
• simplify CI and release workflows while preserving the existing required checks

Validation

• 56 tests pass
• strict mypy passes
• 500-case regression gate passes: 80.4% exact rows, 95.85% component micro-F1
• model regeneration is deterministic
• wheel and sdist pass Twine checks
• fresh wheel installs pass on Python 3.10 and 3.14

No package API or requested release feature was removed.