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>

HERMES.md

@@ -15,6 +15,19 @@ truth for:
 
 When in doubt, check `/opt/homelab-context/` first.
 
+## Runbooks — load, don't rediscover
+
+For the canonical workflows (service health check, config change +
+deploy, client enrollment, incident investigation, and each node
+lifecycle transition), read the matching file in `runbooks/*.md` before
+acting. Each runbook carries its risk class, required inputs, the
+verification command, and a docs-update checklist in its frontmatter —
+classify against `oikos/policy.yaml` using that risk class before any
+mutation. Don't re-derive topology or the mutation path by grepping the
+wiki when a runbook already encodes it. See [OIKOS.md](OIKOS.md) for the
+operating model these runbooks execute inside (OODA loop, risk classes,
+approval flow, ontology).
+
 ## Agent type — how this file gets loaded
 
 | Agent | Loading mechanism |