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>

api/redocly.yaml

@@ -0,0 +1,7 @@
+# Redocly lint config for api/openapi.yaml (CI runs: redocly lint api/openapi.yaml)
+extends:
+  - recommended
+rules:
+  # Every operation declares `default` → RFC 9457 problem+json instead of
+  # enumerating each 4XX (plan R3-3); oapi-codegen handles `default` fine.
+  operation-4xx-response: off