docs: update current validation test count

[Grzanka777]

Summary

• update the README current repository validation count from 78 to 92
• rename the corresponding current-state test
• update the assertion to preserve consistency
• leave all historical 33-test evidence unchanged

Validation

• ruff format --check: pass
• ruff check: pass
• mypy: pass
• pytest: 92 passed
• git diff --check: clean
• staging audit: pass

Safety

• documentation and matching test only
• no planner behavior changes
• no mechanical changes
• no shared contract changes
• no VERSION change
• no Oracle Wisdom changes
• no Codex changes
• root-level planner.md excluded from commit
• no Brain write