sx-loops: each language runs in its own git worktree

Previous version ran all 7 claude sessions in the main working tree on
branch 'architecture'. That would race on git operations and cross-
contaminate commits between languages even though their file scopes
don't overlap. Now each session runs in /root/rose-ash-loops/<lang> on
branch loops/<lang>, created from the current architecture HEAD.

sx-loops-down.sh gains --clean to remove the worktrees; loops/<lang>
branches stay unless explicitly deleted.

Also: second Enter keystroke after the /loop command, since Claude's
input box sometimes interprets the first newline as a soft break.

scripts/sx-loops-down.sh

@@ -1,23 +1,43 @@
 #!/usr/bin/env bash
-# Stop the sx-loops tmux session. Prompts the claude sessions to exit cleanly
-# first (/exit in each window), then kills the tmux session after a grace
-# period. Loops stop immediately; in-progress iterations commit what they have.
+# Stop the sx-loops tmux session. Optionally (--clean) also remove the
+# per-language git worktrees. Loops stop immediately; in-progress iterations
+# commit whatever they have; nothing is pushed that wasn't already.
 set -euo pipefail
 
 SESSION="sx-loops"
+WORKTREE_BASE="/root/rose-ash-loops"
+CLEAN=0
 
-if ! tmux has-session -t "$SESSION" 2>/dev/null; then
-  echo "No sx-loops session running."
-  exit 0
-fi
-
-WINDOWS=$(tmux list-windows -t "$SESSION" -F '#W')
-for w in $WINDOWS; do
-  tmux send-keys -t "$SESSION:$w" "/exit" C-m 2>/dev/null || true
+for arg in "$@"; do
+  case "$arg" in
+    --clean) CLEAN=1 ;;
+    *) echo "Unknown arg: $arg"; exit 2 ;;
+  esac
 done
 
-echo "Sent /exit to all windows. Waiting 5s for clean shutdown..."
-sleep 5
+if tmux has-session -t "$SESSION" 2>/dev/null; then
+  WINDOWS=$(tmux list-windows -t "$SESSION" -F '#W')
+  for w in $WINDOWS; do
+    tmux send-keys -t "$SESSION:$w" "/exit" C-m 2>/dev/null || true
+  done
+  echo "Sent /exit to all windows. Waiting 5s for clean shutdown..."
+  sleep 5
+  tmux kill-session -t "$SESSION"
+  echo "Killed tmux session '$SESSION'."
+else
+  echo "No sx-loops tmux session running."
+fi
 
-tmux kill-session -t "$SESSION"
-echo "Killed sx-loops session."
+if [ "$CLEAN" = "1" ]; then
+  cd "$(dirname "$0")/.."
+  for lang in lua prolog forth erlang haskell js hs; do
+    wt="$WORKTREE_BASE/$lang"
+    if [ -d "$wt" ]; then
+      git worktree remove --force "$wt" 2>/dev/null || rm -rf "$wt"
+      echo "Removed worktree: $wt"
+    fi
+  done
+  git worktree prune
+  echo "Worktree branches (loops/<lang>) are preserved. Delete manually if desired:"
+  echo "  git branch -D loops/lua loops/prolog loops/forth loops/erlang loops/haskell loops/js loops/hs"
+fi