phase 1 review fixes: dedup edges, real export, validation, tests

Review of aa2ca0a found and fixed:
- re-ingest duplicated ALL edges (upsert conflicted on valid_from=now(),
  never fired) — migration 007 dedupes + partial unique index on current
  edges; upsert now targets it. Regression-tested.
- export was a stub that overwrote seeds/*.yaml with 11-byte "version: 1"
  files — implemented real deterministic export (ontology/inventory/policy,
  cognition-layer excluded); round-trip is byte-stable (tested)
- DB password leaked in startup logs (slog JSON bypasses String()) —
  Config now implements slog.LogValuer; regression-tested
- docker-compose had literal '***' as DB password — env-interpolated
- uuid.New() (v4) → uuid.NewV7() per ADR-0005
- no ontology validation on ingest — internal/ontology TypeTree: abstract
  instantiation rejected, relationship endpoints hierarchy-validated,
  cardinality enforced in-transaction, lifecycle states checked, default
  state applied (Phase 1 gate items, R3-1)
- getOrCreateEntityID swallowed non-ErrNoRows errors
- migration runner now holds a session advisory lock on one connection
- Makefile: hardcoded /opt/homebrew/bin/go → go; test-db target

Tests: 4 unit suites + 7 integration tests (env-guarded, throwaway DB per
run): migrate idempotent, seed idempotent + no dup edges, abstract/edge/
cardinality rejection, blast_radius cycle termination, export round-trip.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

migrations/007_relationships_current_unique.up.sql

@@ -0,0 +1,18 @@
+-- Migration 007: one current edge per (source, target, type).
+-- The seed upsert previously conflicted on (source_id, target_id, type,
+-- valid_from) — valid_from is now() at insert, so the conflict never fired
+-- and every re-ingest duplicated all current edges. Dedupe (keep earliest
+-- valid_from), then enforce uniqueness on current edges with a partial
+-- unique index the upsert can target.
+
+DELETE FROM relationships r
+USING relationships keep
+WHERE r.valid_to IS NULL AND keep.valid_to IS NULL
+  AND r.source_id = keep.source_id
+  AND r.target_id = keep.target_id
+  AND r.type      = keep.type
+  AND r.valid_from > keep.valid_from;
+
+CREATE UNIQUE INDEX IF NOT EXISTS uq_rel_current
+    ON relationships(source_id, target_id, type)
+    WHERE valid_to IS NULL;