docs: standardize isolated LLM worktrees (#38)

docs/llm-workflow-runbooks.md

@@ -161,6 +161,62 @@ Legacy environment-only setups keep working unchanged until migrated.
 Each runbook names the **profile role** it runs under, the steps, and a safe
 prompt. Confirm the active profile first (`gitea_get_profile` / `gitea_whoami`).
 
+## Branch worktree isolation
+
+All LLM implementation and review work happens in an isolated branch worktree
+under `branches/`. The main repository checkout is an orchestration checkout:
+use it for status checks, issue creation/claiming, and creating worktrees, but
+do not edit tracked repository files there.
+
+Branch folders are ignored by git via `branches/`, so dirty work in one issue
+does not block starting an unrelated issue in a separate branch folder. No LLM
+may edit another issue's branch folder unless explicitly assigned to that issue.
+No LLM may clean another issue's branch folder unless the PR is merged or closed
+and cleanup is explicitly part of the task.
+
+Implementation work and review work must use separate branch folders. For
+example, an implementation branch might live under
+`branches/fix-issue-123-example`, while a review branch for the resulting PR
+uses its own folder.
+
+Issue creation and claiming may happen from the orchestration checkout:
+
+1. Create or identify the tracking issue.
+2. Claim it with `status:in-progress`.
+3. Create the issue branch worktree.
+4. `cd` into the branch worktree and perform all file edits there.
+
+Preferred helper:
+
+```bash
+scripts/worktree-start fix/issue-123-example
+cd branches/fix-issue-123-example
+```
+
+Because `venv/` is ignored and not copied into new worktrees, run checks with a
+known Python interpreter. Either create a venv inside the branch folder, or use
+the orchestration checkout's venv by explicit path.
+
+Equivalent manual commands:
+
+```bash
+git fetch prgs --prune
+git worktree add -b fix/issue-123-example branches/fix-issue-123-example prgs/master
+cd branches/fix-issue-123-example
+```
+
+For review work, create a separate review worktree/folder instead of reusing the
+author's implementation folder.
+
+Cleanup is explicit and only after merge or close:
+
+```bash
+cd <main-repo>
+git fetch prgs --prune
+git worktree remove branches/fix-issue-123-example
+git branch -d fix/issue-123-example
+```
+
 ### Create an issue / child issues
 
 - **Profile:** issue-manager or author (any profile allowed to create issues).
@@ -172,9 +228,10 @@ prompt. Confirm the active profile first (`gitea_get_profile` / `gitea_whoami`).
 ### Implement an issue and open a PR
 
 - **Profile:** author.
-- **Steps:** claim the issue (`status:in-progress`); branch from latest
-  `master` (`feat/issue-<n>-...` / `fix/...` / `docs/...`); implement narrowly;
-  add/update tests if behavior changes; run the full suite; commit with an
+- **Steps:** claim the issue (`status:in-progress`); create an isolated branch
+  worktree from latest `master` under `branches/` (`feat/issue-<n>-...` /
+  `fix/...` / `docs/...`); `cd` into that worktree; implement narrowly; add or
+  update tests if behavior changes; run the full suite; commit with an
   issue-linked message; open a PR to `master`. **Do not** review or merge your
   own PR.
 - **Prompt:** `Use an author profile to implement issue #N and open a PR to