Oikos Week 2: Service Console v0, change ledger, node relations, runbooks

Adds the shared kernel modules (oikos/policy.py, oikos/relations.py,
oikos/ledger.py) that let every surface — CLI, MCP, context-card
generator — agree on risk classification and ontology graph walks
from one implementation.

homelab CLI: `service <name> explain|health|docs|log|actions|history`
(Service Console v0), `change preflight <service>`, `node <name>
relations`. Restart and client add/remove now append change-ledger
entries (ledger/*.jsonl, committed alongside the change they record).

mcp/server.py mirrors explain/preflight/get_relations/get_change_history
as MCP tools, card-first so agent orientation is one call instead of
several search_docs/get_page round-trips.

oikos/gen-topology.py now also emits a compact context card per host
and service (oikos/cards/*.md) — identity, blast radius, safe actions +
risk class, doc pointer, recent ledger history.

runbooks/*.md: service health check, config change + deploy, client
enrollment, incident investigation, and the five node lifecycle
transitions (provision/activate/migrate/deprecate/destroy), each with
machine-readable frontmatter (risk class, inputs, verification,
docs-update checklist). Wired into HERMES.md so agents load these
instead of rediscovering topology per-task.

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

oikos/cards/host-apps.md

@@ -0,0 +1,21 @@
+# apps (host:apps)
+
+- kind: lxc (LXC 105)
+- state: active
+- runs-on: host:hubris
+- role: docker-apps
+- address: 192.168.8.205 (mesh: tailscale:apps)
+- mounts: /mnt/library
+- doc: containers/105-apps.md
+- secrets: enrolled (age key present)
+
+## Blast radius
+- impacts: service:artifacto, service:homelab_mcp, service:secrets_issuance
+- affected by: host:hubris, mount:/mnt/library, repo:dtoro/Artifacto, repo:dtoro/Homelab-Docs
+- full blast radius: service:artifacto, service:homelab_mcp, service:secrets_issuance
+
+## Safe actions
+- see the services this host runs for action-level risk classes
+
+## Recent changes
+- (none yet)