feat(e1): engine improvements — TextPk + Real + TextArchiveEnum + TextPairWithMetadata
4 additive FieldKind/EdgeKeyKind variants addressing M1 dogfood +
M4/M5 flags. Backward-compat — existing schemas unchanged.
FieldKind::TextPk — TEXT PRIMARY KEY (kei-chat-store UUID sessions)
FieldKind::Real + RealDefault(f64) — REAL columns (kei-chat-store cost)
FieldKind::TextArchiveEnum — archive verb writes string sentinel instead of 1
EdgeKeyKind::TextPairWithMetadata — src_path/dst_path + id/weight/created_at/extra
Archive verb now dispatches: IntegerFlag writes 1, TextArchiveEnum writes sentinel.
Link/rank handle TextPairWithMetadata via generic weight+id propagation.
PK helpers in verbs/pk.rs abstract integer vs text primary key.
Engine decomposed to stay under 200 LOC:
- schema.rs (149) + field.rs (94, new) + ddl.rs (157, new)
- verbs/pk.rs + create_defaults.rs split from create.rs
Tests: 40/40 (was 32, +8 real_text_pk_smoke).
Sister crates verified backward-compat:
- kei-task 9/9, kei-chat-store 5/5, kei-content-store 4/4
- kei-social-store 5/5, kei-crossdomain 5/5, kei-sage 28/28
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>