docs: compact Controller Handoff as default format (#108)

Make the nine-line compact Controller Handoff the default end-of-task
format; reserve the long Controller Handoff Summary for high-risk/complex
tasks (merge/tag/release, failed validation, blocked gates, secrets/prod,
complicated owner decisions, cross-repo state, or explicit owner request).
Compact form is for controller-LLM readability, safety confirmations are
never omitted, and PR bodies still carry full review detail.

Updates SKILL.md §K, llm-workflow-runbooks.md, and the start-issue /
review-pr templates. Documentation only.

Refs #101. Closes #108.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

skills/llm-project-workflow/templates/review-pr.md

@@ -33,6 +33,6 @@ Steps:
    - Eligibility: passed/failed
 
 Handoff: reviewer identity, PR author, scope verdict, checks + results, decision —
-formatted as the Controller Handoff Summary (SKILL.md §K); if you could not
-merge, name the exact gate that blocked it.
+formatted per SKILL.md §K (compact by default; long form if a merge happened
+or a gate blocked you); if you could not merge, name the exact gate.
 ```