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/service-matrix.md

@@ -0,0 +1,19 @@
+# matrix (service:matrix)
+
+- backend: host:elementsynapse
+- url: https://matrix.hubris.network
+- doc: containers/118-elementsynapse.md
+- risk notes: alert/approval channel for Oikos — outage silences agent escalation
+
+## Blast radius
+- impacts: (none)
+- affected by: host:elementsynapse
+
+## Safe actions
+- health-check — read_only (approval: none)
+- view-logs — read_only (approval: none)
+- view-docs — read_only (approval: none)
+- restart — reversible_low (approval: none)
+
+## Recent changes
+- (none yet)