Oikos Week 1: kernel policy, ontology, service contract, topology gen

Adds the Oikos agent-OS kernel: oikos/policy.yaml (risk classes +
approval rules for every homelab/MCP command), oikos/ontology.yaml
(8-domain systems model, typed relationships, node lifecycle), and
OIKOS.md (OODA loop operating brief, linked from AGENTS.md).

Extends inventory.yaml with a stable service contract (doc_page,
config_repo, risk_notes) on all 17 services, and a structured
archaeology: section for the 13 destroyed LXCs (was scattered
comments + a narrative table). Fixes stale drift found in the
process: authentik's backend pointed at a retired LXC (124); core
has run on the VPS since 2026-05-31.

Adds oikos/gen-topology.py, generating infrastructure/topology.md
(Mermaid compute/ingress + storage views) from inventory.yaml.
build_host_files.py now carries state/storage/depends_on into
generated hosts/*.yaml.

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

hosts/dns.yaml

@@ -5,6 +5,7 @@ name: dns
 kind: lxc
 os: linux
 role: dns-server
+state: active
 host: hubris
 pve_id: 107
 lan_ip: 192.168.8.2
@@ -14,13 +15,13 @@ mesh_globals:
   - netbird
   - tailscale
 runs:
-- authentik
+- dns
 services_hosted:
-- name: authentik
-  url: https://auth.hubris.network
+- name: dns
   backend: dns
-  dns: null
   note: Technitium DNS, split-horizon zone
+  doc_page: containers/107-dns.md
+  risk_notes: "LAN-wide resolver \u2014 misconfig breaks name resolution for every client"
 notes:
 - Technitium DNS, split-horizon zone for *.hubris.network
 - Primary DNS for 192.168.8.0/24 LAN (inventory.services.dns references this)