docs: reshape runbooks into .agents/skills/<name>/SKILL.md (phase 4)

Problem: runbooks are agent-executable procedures but lived at the repo root,
separate from the other agent instruction now under .agents/.

Change:
- Move runbooks/<name>.md -> .agents/skills/<name>/SKILL.md (folder per skill,
  matching the wiki-hq skills layout). Frontmatter (name, risk_class, inputs,
  verification, docs_update_checklist, transition) preserved.
- Rewrite links (inbound from plans; between-skill siblings) via the move map.
- Update prose references in AGENTS.md, HERMES.md, .agents/OIKOS.md, and the
  operations schema; fix a pre-existing stale link to operations/commands.md.

No code consumed runbooks/ by path, so nothing else changes.

Verification: all SKILL.md frontmatter parses with valid risk_class; every
lifecycle transition resolves to an oikos/ontology.yaml state; broken-link
count 127 -> 126 (fixed one, introduced none).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.agents/OIKOS.md

@@ -40,7 +40,7 @@ one pass through **Observe → Orient → Decide → Act**:
 |---|---|---|
 | Host / Service | topology entities | `inventory.yaml` (+ generated `hosts/*.yaml`) |
 | Secret | SOPS+age encrypted value, per-client recipients | `secrets/` + `.sops.yaml` |
-| Runbook | executable workflow with risk class + verification | `runbooks/` (Week 2) |
+| Runbook | executable workflow with risk class + verification | `.agents/skills/<name>/SKILL.md` |
 | Signal | something needing attention, with lifecycle | `signals/` ledger (Week 3) |
 | Change | one mutation: who, what, risk, approval, verification | `ledger/` (Week 2) |
 | Approval | short-TTL signed grant for a gated action | approval engine (Week 3) |