docs: update ZOD_SCHEMA_AUDIT_REPORT.md to reflect all resolved issues

- Update executive summary metrics (z.any: 397→9, z.unknown: 8→350, describe: 5026→5691)
- Mark all P0/P1/P2 recommendations as resolved
- Update per-directory statistics with current counts
- Update quality grade from B+ to A-
- Update all section-specific issue notes with resolution status

Co-authored-by: hotlong <50353452+hotlong@users.noreply.github.com>

Author: Copilot