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/domains/operations/schema.md

@@ -20,8 +20,8 @@ versioned, reviewable, and reachable by MCP `get_page`/`search_docs` like any ot
 
 ## Runbooks
 
-Repeatable procedures live in `runbooks/<name>.md` with YAML front-matter that the Oikos policy and
-lifecycle machinery reads:
+Repeatable procedures are skills — one folder per skill at `.agents/skills/<name>/SKILL.md`, with
+YAML front-matter that the Oikos policy and lifecycle machinery reads:
 
 ```yaml
 ---