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>

runbooks/config-change-deploy.md

@@ -0,0 +1,34 @@
+---
+name: config-change-deploy
+risk_class: config_mutation
+inputs: [service_name, change_description]
+verification: "curl -sf <service_url> (or homelab service <name> health)"
+docs_update_checklist: [doc_page, changelog]
+---
+
+# Config change + deploy
+
+Goal: change a tracked config repo (Caddy, Gitea customizations, an app's
+own repo) and get it live, safely.
+
+1. `homelab change preflight <service>` — current health, the service's
+   `config_repo`, its risk class, and the verification command to run
+   after. If risk class requires approval (`config_mutation` or
+   `destructive`), stop and get operator sign-off before editing — see
+   `oikos/policy.yaml`.
+2. Clone/pull the `config_repo` (never edit the backend's working tree
+   directly — tracked configs change by commit + push, per
+   [OIKOS.md](../OIKOS.md) conventions).
+3. Make the change, commit, push to `main`.
+4. The Gitea webhook fires the deploy pipeline for that repo (see
+   [infrastructure/auto-deploy.md](../infrastructure/auto-deploy.md) for
+   the exact receiver/reload for this service).
+5. Run the preflight's verification command. If it fails, check
+   `homelab service <name> log` for the reload/restart error.
+6. Record the change: once `oikos/ledger.py` is wired into deploy tooling
+   (Week 3), this is automatic; until then, note the change and outcome
+   in the relevant investigation/plan doc.
+
+Docs-update checklist: update the service's `doc_page` if the change
+alters its behavior, ingress route, or ownership; add a changelog entry
+if the page has one.