docs: reframe root README for AI-OS overview

[sergstack]

Summary

• Adds a user-facing Russian showcase section to README_RU.md: entry points, the 22-method Analytics framing, repository map, evidence links, and honest domain boundaries.
• Preserves the current bilingual root README and its governance/sync boundaries from main.
• States that a bicycle-domain demo is not present rather than implying one exists.

Conflict resolution

• Rebased onto current main in an isolated worktree.
• Kept current main where older branch status claims conflicted with current governance or source-fingerprint records.
• The PR is now mergeable; its remaining BLOCKED merge state is the repository approval gate, not a content conflict.

Validation

• python3 -m pytest -rA tests/test_live_behavioral_benchmark.py — 5 passed.
• python3 -m pytest -rA tests/test_validation_scripts.py — 29 passed.
• git diff --check origin/main...HEAD passed.

Rollback

• Revert bcd1b1d for the README addition; review the three benchmark commits independently before merge.

[github-actions]

Merge gate: protected paths changed. Auto-merge is disabled and owner review is required via CODEOWNERS.