Enables @typescript-eslint/no-unsafe-member-access globally. Tests and 41
heavy source files (>5 violations each) are exempted via per-file overrides
with current violation counts annotated for follow-up PRs. Fixes 124
violations across 51 source files using narrow type assertions, instanceof
Error guards, and proper structural types instead of blanket any casts.
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>