fix(mcp): allow create_issue from clean control checkout (#749)

Provide a narrow phase-scoped bootstrap so gitea_create_issue can run from
a clean canonical control checkout when no issue number—and therefore no
issue-backed worktree—can exist yet. Dirty roots, non-base branches, base
races, foreign workspaces, and all post-creation author mutations remain
fail-closed under the ordinary branches-only guard.

Closes #749.

docs/llm-workflow-runbooks.md

@@ -48,6 +48,16 @@ It extracts the issue-first, isolated-worktree, no-self-review, profile-safety,
 merge-cleanup, fail-closed, and recovery rules into a reusable package that can
 be adapted to other repositories.
 
+### Sanctioned first mutation: `create_issue` from clean control (#749)
+
+Creating a tracking issue has no issue number yet, so no `branches/issue-<N>-*`
+worktree can exist. The sanctioned path is: clean canonical control checkout
+(accepted base branch, base-equivalent to live master, no tracked dirt) →
+resolve exact `create_issue` → `gitea_create_issue`. After the issue exists,
+all further author mutations require a registered issue-backed worktree and
+lock. Do not improvise with dummy directories, borrowed worktrees, or pre-issue
+worktrees. See `skills/llm-project-workflow/workflows/create-issue.md` §18a.
+
 ## Principle: the profile is the role, not the LLM
 
 ```text