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>

plans/2026-07-06-consolidate-oikos-control-plane-onto-mac-mini.md

@@ -711,7 +711,8 @@ CREATE TABLE entity_types (
     is_abstract   BOOLEAN NOT NULL DEFAULT false,       -- abstract types can't be instantiated
     domain        TEXT NOT NULL,             -- 'physical','compute','network','storage',
                                              -- 'software','identity','policy','cognition'
-    layer         TEXT NOT NULL CHECK (layer IN ('infrastructure','governance','cognition')),
+    layer         TEXT NOT NULL CHECK (layer IN ('meta','infrastructure','governance','cognition')),
+                                             -- 'meta' is reserved for the abstract root type 'entity'
     description   TEXT,
     lifecycle_id  TEXT REFERENCES lifecycle_defs(id),
     attribute_schema JSONB,                  -- JSON Schema for entities.attributes (D2)
@@ -727,8 +728,8 @@ CREATE TABLE relationship_types (
     inverse       TEXT,
     source_type   TEXT NOT NULL REFERENCES entity_types(name),  -- MAY be abstract;
     target_type   TEXT NOT NULL REFERENCES entity_types(name),  -- validation walks hierarchy
-    cardinality   TEXT NOT NULL CHECK (cardinality IN
-                    ('one-to-one','one-to-many','many-to-many')),
+    cardinality   TEXT NOT NULL CHECK (cardinality IN          -- source→target multiplicity
+                    ('one-to-one','one-to-many','many-to-one','many-to-many')),
     description   TEXT,
     created_at    TIMESTAMPTZ NOT NULL DEFAULT now()
 );