oikos phase 0: ontology + inventory + policy seeds, OpenAPI contract, ADRs

- seeds/ontology.yaml: 59 entity types (5 abstract, is-a hierarchy), 46
  relationship types with cardinality, 6 lifecycles with terminal states
  and named precondition checks
- seeds/inventory.yaml: 110 entities / 142 relationships translated from
  legacy inventory.yaml (fleet, services, ingress, storage, governance,
  archaeology); thin spots marked for backfill
- seeds/policy.yaml: 4 risk classes, 27 approval rules (hierarchy-aware,
  per-entity overrides), autonomy kill-switch off (cold start)
- api/openapi.yaml: full v1 REST contract (40 paths), RFC 9457 errors,
  cursor pagination, idempotency, ETag/If-Match, scopes; redocly-clean
- docs/adr/0001-0010: initial architecture decision records
- scripts/validate-seeds.py: Phase 0 gate — hierarchy, lifecycles,
  endpoints, cardinality, policy cross-refs (0 errors)
- plan: layer CHECK gains 'meta' (root type), cardinality gains
  'many-to-one'

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

docs/adr/0003-db-native-ontology-yaml-seeds.md

@@ -0,0 +1,23 @@
+# ADR 0003 — DB-native ontology with YAML seed manifests
+
+Status: accepted (2026-07-07) · Plan: rev 3, R3-1
+
+## Context
+Rev 1 kept inventory/ontology/policy as YAML files parsed at runtime.
+Agents need graph queries (blast radius), transactional mutations with
+audit, and a future UI needs to edit the model without file round-trips.
+
+## Decision
+The DB is the runtime source of truth. entity_types form an is-a hierarchy
+(parent_type, is_abstract); relationship endpoint constraints may name
+abstract types and validation walks the hierarchy. YAML files under seeds/
+bootstrap the DB (idempotent, content-hashed via seed_versions) and serve
+DR; `GET /api/v1/export` regenerates them for version control (round-trip
+byte-stable, tested in CI).
+
+## Consequences
+- Ontology changes are API calls (policy-gated), not redeploys.
+- Seeds can drift from DB between exports — export is part of the routine
+  (commit after meaningful model edits).
+- Abstract types let policy rules and relationships bind once at the right
+  altitude (e.g. `compute-entity provides service`).