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/0005-uuidv7-plus-slug-identity.md

@@ -0,0 +1,18 @@
+# ADR 0005 — UUIDv7 + slug entity identity
+
+Status: accepted (2026-07-07) · Plan: rev 3, R3-5 (resolves audit D1)
+
+## Context
+Rev 2 used TEXT primary keys ('host:hubris') — renames break FKs, and
+date-string signal IDs are race-prone.
+
+## Decision
+Primary keys are UUIDv7 (time-ordered, generated in Go). Every entity also
+carries a unique human slug ('host:hubris'); (type, name) is unique too.
+The API accepts UUID or slug everywhere; slugs may change (rename), UUIDs
+never do.
+
+## Consequences
+- Renames are metadata updates; history and edges survive.
+- UUIDv7's time-ordering keeps B-tree inserts append-mostly.
+- Seeds and exports use slugs (human-diffable); ingest resolves to UUIDs.