fix: extract restore_to_backlog() to eliminate duplicate label reset pattern

The cleanup_labels + curl POST + CLAIMED=false pattern was duplicated
across dev-agent.sh (idle_timeout and crashed cases) and phase-handler.sh
(PHASE:crashed handler), triggering duplicate-detection CI failure.

Extract restore_to_backlog() shared helper; call it from all three sites.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

dev/dev-agent.sh

@@ -131,6 +131,16 @@ cleanup_labels() {
     "${API}/issues/${ISSUE}/labels/${IN_PROGRESS_LABEL_ID}" >/dev/null 2>&1 || true
 }
 
+restore_to_backlog() {
+  cleanup_labels
+  curl -sf -X POST \
+    -H "Authorization: token ${CODEBERG_TOKEN}" \
+    -H "Content-Type: application/json" \
+    "${API}/issues/${ISSUE}/labels" \
+    -d "{\"labels\":[${BACKLOG_LABEL_ID}]}" >/dev/null 2>&1 || true
+  CLAIMED=false  # Don't unclaim again in cleanup()
+}
+
 CLAIMED=false
 cleanup() {
   rm -f "$LOCKFILE" "$STATUSFILE"
@@ -750,13 +760,7 @@ case "${_MONITOR_LOOP_EXIT:-}" in
     echo "{\"issue\":${ISSUE},\"pr\":${PR_NUMBER:-0},\"reason\":\"${_MONITOR_LOOP_EXIT:-idle_timeout}\",\"ts\":\"$(date -u +%Y-%m-%dT%H:%M:%SZ)\"}" \
       >> "${FACTORY_ROOT}/supervisor/escalations-${PROJECT_NAME}.jsonl"
     # Restore labels: remove in-progress, add backlog
-    cleanup_labels
-    curl -sf -X POST \
-      -H "Authorization: token ${CODEBERG_TOKEN}" \
-      -H "Content-Type: application/json" \
-      "${API}/issues/${ISSUE}/labels" \
-      -d "{\"labels\":[${BACKLOG_LABEL_ID}]}" >/dev/null 2>&1 || true
-    CLAIMED=false  # Don't unclaim again in cleanup()
+    restore_to_backlog
     if [ -n "${PR_NUMBER:-}" ]; then
       log "keeping worktree (PR #${PR_NUMBER} still open)"
     else
@@ -771,13 +775,7 @@ case "${_MONITOR_LOOP_EXIT:-}" in
     # Belt-and-suspenders: _on_phase_change(PHASE:crashed) handles primary
     # cleanup, but ensure labels and files are cleaned up if callback was
     # interrupted (e.g. set -e propagation).
-    cleanup_labels
-    curl -sf -X POST \
-      -H "Authorization: token ${CODEBERG_TOKEN}" \
-      -H "Content-Type: application/json" \
-      "${API}/issues/${ISSUE}/labels" \
-      -d "{\"labels\":[${BACKLOG_LABEL_ID}]}" >/dev/null 2>&1 || true
-    CLAIMED=false
+    restore_to_backlog
     if [ -z "${PR_NUMBER:-}" ]; then
       cleanup_worktree
     fi

dev/phase-handler.sh

@@ -726,14 +726,7 @@ $(printf '%s' "$REFUSAL_JSON" | head -c 2000)
       >> "${FACTORY_ROOT}/supervisor/escalations-${PROJECT_NAME}.jsonl"
 
     # Restore backlog label so issue can be retried
-    cleanup_labels
-    curl -sf -X POST \
-      -H "Authorization: token ${CODEBERG_TOKEN}" \
-      -H "Content-Type: application/json" \
-      "${API}/issues/${ISSUE}/labels" \
-      -d "{\"labels\":[${BACKLOG_LABEL_ID}]}" >/dev/null 2>&1 || true
-
-    CLAIMED=false  # Don't unclaim again in cleanup()
+    restore_to_backlog
     if [ -n "${PR_NUMBER:-}" ]; then
       log "keeping worktree (PR #${PR_NUMBER} still open)"
     else