The date field gh_pushed was written as the literal string 'N/A' when
GitHub data was unavailable (fast_enrich, gemini_utils). That non-date
string then reached datetime.fromisoformat() downstream. Now writes None
(which all readers already handle); gh_license keeps its 'N/A' string
sentinel since it is a displayed value, not a date.
Also hardens the twin fromisoformat() call in agentic_curator's MVQ
penalty check (guards N/A/None and wraps parsing) so a bad value can't
crash a curation batch.
Adds scripts/normalize_gh_pushed.py to clean the 281 existing inventory
entries (run in CI to avoid SQLite float-serialization churn — see
script docstring).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
