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/hubris.yaml

@@ -5,6 +5,7 @@ name: hubris
 kind: proxmox-host
 os: linux
 role: hypervisor
+state: active
 lan_ip: 192.168.8.77
 mesh:
   netbird:
@@ -28,6 +29,8 @@ services_hosted:
   url: https://proxmox.hubris.network
   backend: hubris
   port: 8006
+  doc_page: hosts/hubris.md
+  risk_notes: "hypervisor UI \u2014 changes here affect every guest on the node"
 age_pubkey: age1xkklkvnk5z0fsnh6cfgv70hy9ksfy8rdprwerzw4yk3p4p7cxcqs2yvpz6
 see_also:
 - hosts/hubris.md