SQLite datetime comparison fails lexicographically across ISO-T and
space-separator formats: '2026-03-27 18:00:14' < '2026-03-27T17:43:04+00:00'
because space (0x20) < T (0x54). PRs merged same-day but earlier than the
commit hour were silently excluded from the time-proximity cascade.
Shaga's 3 stigmergic-coordination claims resolved to PR #2032 (later, wrong)
instead of #2025 (earlier, correct). Fixed by wrapping both sides in
datetime(), which normalizes to space-separator before comparison.
Verified: all 3 Shaga claims now resolve to #2025 via git_time_proximity.
No change to totals (126 originator events, 5 proximity hits) — the fix
corrects WHICH PR each proximity-matched claim resolves to, not whether.
Caught by Ganymede review of 1d6b515.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>