Spawn agents with cwd set to their worktree

Resolves issue #86 by having the spawn-issues orchestrator create worktrees
upfront and pass the worktree paths to agents, instead of having agents
create their own worktrees in sibling directories outside the sandbox.

Changes:
- spawn-issues orchestrator creates all worktrees before spawning agents
- issue-worker, pr-fixer, code-reviewer accept optional WORKTREE_PATH
- When WORKTREE_PATH is provided, agents work directly in that directory
- Backward compatible: agents still support creating their own worktrees
  if WORKTREE_PATH is not provided
- Orchestrator handles all worktree cleanup after agents complete
- Eliminates permission denied errors from agents trying to access
  sibling worktree directories

This ensures agents operate within their sandbox while still being able to
work with isolated git worktrees for parallel implementation.

Closes #86

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

commands/spawn-issues.md

@@ -63,13 +63,34 @@ Usage: /spawn-issues <issue-number> [<issue-number>...]
 Example: /spawn-issues 42 43 44
 ```
 
-### Step 2: Get Repository Info
+### Step 2: Get Repository Info and Setup Worktrees
 
 ```bash
 REPO_PATH=$(pwd)
-REPO_NAME=$(basename $REPO_PATH)
+REPO_NAME=$(basename $REPO_NAME)
+
+# Create parent worktrees directory
+mkdir -p "${REPO_PATH}/../worktrees"
+WORKTREES_DIR="${REPO_PATH}/../worktrees"
 ```
 
+For each issue, create the worktree upfront:
+```bash
+# Fetch latest from origin
+cd "${REPO_PATH}"
+git fetch origin
+
+# Get issue details for branch naming
+ISSUE_TITLE=$(tea issues <ISSUE_NUMBER> | grep "TITLE" | head -1)
+BRANCH_NAME="issue-<ISSUE_NUMBER>-<kebab-title>"
+
+# Create worktree for this issue
+git worktree add "${WORKTREES_DIR}/${REPO_NAME}-issue-<ISSUE_NUMBER>" \
+  -b "${BRANCH_NAME}" origin/main
+```
+
+Track the worktree path for each issue.
+
 ### Step 3: Spawn All Issue Workers
 
 For each issue number, spawn a background issue-worker agent and track its task_id:
@@ -106,12 +127,11 @@ Context:
 - Repository path: <REPO_PATH>
 - Repository name: <REPO_NAME>
 - Issue number: <NUMBER>
+- Worktree path: <WORKTREE_PATH>
 
 Process:
 1. Setup worktree:
-   cd <REPO_PATH> && git fetch origin
-   git worktree add ../<REPO_NAME>-issue-<NUMBER> -b issue-<NUMBER>-<short-title> origin/main
-   cd ../<REPO_NAME>-issue-<NUMBER>
+   cd <WORKTREE_PATH>
 
 2. Get issue: tea issues <NUMBER> --comments
 
@@ -124,7 +144,7 @@ Process:
 6. Create PR: tea pulls create --title "[Issue #<NUMBER>] <title>" --description "Closes #<NUMBER>\n\n..."
    Capture the PR number.
 
-7. Cleanup: cd <REPO_PATH> && git worktree remove ../<REPO_NAME>-issue-<NUMBER> --force
+7. Cleanup: No cleanup needed - orchestrator handles worktree removal
 
 8. Output EXACTLY this format (orchestrator parses it):
    ISSUE_WORKER_RESULT
@@ -182,8 +202,17 @@ implementing → (worker done) → reviewing → (approved) → DONE
 
 ### Step 5: Spawn Reviewers and Fixers
 
-When spawning reviewers, pass the PR number AND branch name from the issue worker result.
-Each reviewer/fixer uses its own worktree for isolation - this prevents parallel agents from interfering with each other.
+When spawning reviewers/fixers, create worktrees for them and pass the path.
+
+For review, create a review worktree from the PR branch:
+```bash
+cd "${REPO_PATH}"
+git fetch origin
+git worktree add "${WORKTREES_DIR}/${REPO_NAME}-review-<PR_NUMBER>" \
+  origin/<BRANCH_NAME>
+```
+
+Pass this worktree path to the reviewer/fixer agents.
 
 **Code Reviewer:**
 ```
@@ -199,15 +228,12 @@ You are a code-reviewer agent. Review PR #<PR_NUMBER> autonomously.
 
 Context:
 - Repository path: <REPO_PATH>
-- Repository name: <REPO_NAME>
 - PR number: <PR_NUMBER>
-- PR branch: <BRANCH_NAME>
+- Worktree path: <WORKTREE_PATH>
 
 Process:
-1. Setup worktree for isolated review:
-   cd <REPO_PATH> && git fetch origin
-   git worktree add ../<REPO_NAME>-review-<PR_NUMBER> origin/<BRANCH_NAME>
-   cd ../<REPO_NAME>-review-<PR_NUMBER>
+1. Move to worktree:
+   cd <WORKTREE_PATH>
 
 2. Get PR details: tea pulls <PR_NUMBER> --comments
 
@@ -221,7 +247,7 @@ Process:
 
 5. Post review comment: tea comment <PR_NUMBER> "<review summary>"
 
-6. Cleanup: cd <REPO_PATH> && git worktree remove ../<REPO_NAME>-review-<PR_NUMBER> --force
+6. Cleanup: No cleanup needed - orchestrator handles worktree removal
 
 7. Output EXACTLY this format:
    REVIEW_RESULT
@@ -267,17 +293,14 @@ You are a pr-fixer agent. Address review feedback on PR #<NUMBER>.
 
 Context:
 - Repository path: <REPO_PATH>
-- Repository name: <REPO_NAME>
 - PR number: <NUMBER>
+- Worktree path: <WORKTREE_PATH>
 
 Process:
-1. Get feedback: tea pulls <NUMBER> --comments
+1. Move to worktree:
+   cd <WORKTREE_PATH>
 
-2. Setup worktree from PR branch:
-   cd <REPO_PATH> && git fetch origin
-   git worktree add ../<REPO_NAME>-pr-<NUMBER> origin/<branch-name>
-   cd ../<REPO_NAME>-pr-<NUMBER>
-   git checkout <branch-name>
+2. Get feedback: tea pulls <NUMBER> --comments
 
 3. Address each piece of feedback
 
@@ -285,7 +308,7 @@ Process:
    git add -A && git commit -m "Address review feedback\n\nCo-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>"
    git push
 
-5. Cleanup: cd <REPO_PATH> && git worktree remove ../<REPO_NAME>-pr-<NUMBER> --force
+5. Cleanup: No cleanup needed - orchestrator handles worktree removal
 
 6. Output EXACTLY:
    PR_FIXER_RESULT
@@ -296,9 +319,29 @@ Process:
 Work autonomously. If feedback is unclear, make reasonable judgment calls.
 ```
 
+## Worktree Cleanup
+
+After all issues reach terminal state, clean up all worktrees:
+
+```bash
+# Remove all worktrees created for this run
+for worktree in "${WORKTREES_DIR}"/*; do
+  if [ -d "$worktree" ]; then
+    cd "${REPO_PATH}"
+    git worktree remove "$worktree" --force
+  fi
+done
+
+# Remove worktrees directory if empty
+rmdir "${WORKTREES_DIR}" 2>/dev/null || true
+```
+
+**Important:** Always clean up worktrees, even if the orchestration failed partway through.
+
 ## Error Handling
 
 - If an issue-worker fails, continue with others
 - If a review fails, mark as "review-failed" and continue
 - If pr-fixer fails after 3 iterations, mark as "needs-manual-review"
 - Always report final status even if some items failed
+- Always clean up all worktrees before exiting