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/start-issue.md

@@ -37,6 +37,6 @@ Steps:
 8. Stop before review/merge — you are the author.
 
 Handoff: issue #, branch, worktree path, files changed, checks + results, PR URL —
-formatted as the Controller Handoff Summary (SKILL.md §K); end with
-"Review needed — PR is open".
+formatted as the compact Controller Handoff (SKILL.md §K; long form only on
+the high-risk triggers); Review line: "Review needed — PR is open".
 ```