feat(cleanup): detect and remove merged worktrees

Enhances /cleanup to identify active worktrees whose branch has
already been merged into the default branch, and offers to remove
them. Previously only orphaned worktrees (stale git entries) were
detected — merged-but-lingering worktrees were invisible to cleanup.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: jwaldrip

plugin/skills/cleanup/SKILL.md

@@ -1,11 +1,11 @@
 ---
-description: Remove orphaned AI-DLC worktrees
+description: Remove orphaned and merged AI-DLC worktrees
 disable-model-invocation: true
 ---
 
 ## Name
 
-`ai-dlc:cleanup` - Remove orphaned AI-DLC worktrees.
+`ai-dlc:cleanup` - Remove orphaned and merged AI-DLC worktrees.
 
 ## Synopsis
 
@@ -17,12 +17,12 @@ disable-model-invocation: true
 
 **User-facing command** - Run this to clean up stale worktrees left behind by interrupted sessions.
 
-Scans `.ai-dlc/worktrees/` for worktree directories and removes any that are orphaned (the backing git worktree entry is stale or the directory is left over from a crashed session).
+Scans `.ai-dlc/worktrees/` for worktree directories and removes any that are orphaned (the backing git worktree entry is stale or the directory is left over from a crashed session) or merged (the worktree's branch has already been merged into the default branch).
 
 This does not:
 - Clear AI-DLC state (use `/reset` for that)
-- Delete branches or commits
-- Affect active worktrees with running sessions
+- Delete unmerged branches or commits
+- Affect active worktrees whose branches have not been merged
 
 ## Implementation
 
@@ -57,20 +57,48 @@ if [ -z "$DIRS" ]; then
 fi
 ```
 
-### Step 2: Identify Orphaned Worktrees
+### Step 2: Identify Orphaned, Merged, and Active Worktrees
 
 ```bash
 # Get list of valid worktree paths from git
 VALID_WORKTREES=$(git worktree list --porcelain | grep '^worktree ' | sed 's/^worktree //')
 
+# Determine the default branch
+DEFAULT_BRANCH=$(git symbolic-ref refs/remotes/origin/HEAD 2>/dev/null | sed 's|refs/remotes/origin/||')
+if [ -z "$DEFAULT_BRANCH" ]; then
+  # Fallback: try common names
+  for candidate in main master; do
+    if git rev-parse --verify "refs/heads/$candidate" &>/dev/null; then
+      DEFAULT_BRANCH="$candidate"
+      break
+    fi
+  done
+fi
+
+# Get the list of branches already merged into the default branch
+MERGED_BRANCHES=$(git branch --merged "$DEFAULT_BRANCH" 2>/dev/null | sed 's/^[* ]*//')
+
 ORPHANED=()
+MERGED=()
+MERGED_BRANCHES_MAP=()   # parallel array: branch name for each merged entry
 ACTIVE=()
 
 for dir in $DIRS; do
+  slug=$(basename "$dir")
   if echo "$VALID_WORKTREES" | grep -qF "$dir"; then
-    ACTIVE+=("$(basename "$dir")")
+    # Active worktree — check if its branch is merged
+    BRANCH=$(git worktree list --porcelain | awk -v path="$dir" '
+      /^worktree / { wt=$0; sub(/^worktree /,"",wt) }
+      /^branch /   { if (wt == path) { sub(/^branch refs\/heads\//,""); print; exit } }
+    ')
+    if [ -n "$BRANCH" ] && echo "$MERGED_BRANCHES" | grep -qxF "$BRANCH"; then
+      MERGED+=("$slug")
+      MERGED_BRANCHES_MAP+=("$BRANCH")
+    else
+      ACTIVE+=("$slug")
+    fi
   else
-    ORPHANED+=("$(basename "$dir")")
+    ORPHANED+=("$slug")
   fi
 done
 ```
@@ -82,21 +110,26 @@ Show the user what was found:
 ```
 ## AI-DLC Worktree Cleanup
 
-**Active worktrees:** {count}
-{list of active worktree names, if any}
-
 **Orphaned worktrees:** {count}
 {list of orphaned worktree names, if any}
+
+**Merged worktrees (safe to remove):** {count}
+{list of merged worktree names with branch names, e.g. "slug (ai-dlc/slug/main)"}
+
+**Active worktrees:** {count}
+{list of active worktree names, if any}
 ```
 
 If there are orphaned worktrees, ask the user to confirm removal using `AskUserQuestion`.
 
-If there are no orphaned entries but there are active worktrees, ask whether to force-remove all worktrees (with a warning that this will interrupt any running sessions).
+If there are merged worktrees, ask the user (separately from orphaned confirmation) whether to remove them using `AskUserQuestion`. Explain that their branches are already merged into the default branch so removal is safe.
+
+If there are no orphaned or merged entries but there are active worktrees, ask whether to force-remove all worktrees (with a warning that this will interrupt any running sessions).
 
 If there is nothing to clean up, output:
 
 ```
-No orphaned worktrees found. Everything is clean.
+No orphaned or merged worktrees found. Everything is clean.
 ```
 
 ### Step 4: Remove
@@ -109,6 +142,23 @@ for name in "${ORPHANED[@]}"; do
   rm -rf "${REPO_ROOT}/.ai-dlc/worktrees/${name}"
 done
 
+# Remove merged worktrees (if user confirmed)
+for i in "${!MERGED[@]}"; do
+  name="${MERGED[$i]}"
+  branch="${MERGED_BRANCHES_MAP[$i]}"
+  # Remove the worktree (no --force needed since branch is merged)
+  git worktree remove "${REPO_ROOT}/.ai-dlc/worktrees/${name}" 2>/dev/null
+  # Delete the merged branch (safe — git -d refuses if not merged)
+  git branch -d "$branch" 2>/dev/null
+  # Clean up the intent spec directory if it exists
+  if [ -d "${REPO_ROOT}/.ai-dlc/${name}" ]; then
+    # Ask user before removing spec directory
+    # Use AskUserQuestion: "Remove spec directory .ai-dlc/${name}/?"
+    # If confirmed:
+    rm -rf "${REPO_ROOT}/.ai-dlc/${name}"
+  fi
+done
+
 # If user chose to force-remove active worktrees too:
 for name in "${FORCE_REMOVE[@]}"; do
   git worktree remove --force "${REPO_ROOT}/.ai-dlc/worktrees/${name}" 2>/dev/null
@@ -125,4 +175,5 @@ Output:
 Cleanup complete.
 
 Removed {count} orphaned worktree(s).
+Removed {count} merged worktree(s) and their branches.
 ```