fix(deploy): one-shot cleanup of orphan overlay dirs after globals removal

Migration 0005_script_overlays drops the legacy l4d2center_maps /
cedapug_maps overlay rows but leaves their /var/lib/left4me/overlays/{id}
directories on disk. When the web app subsequently creates a new overlay
and AUTOINCREMENT issues an id matching one of those orphans,
create_overlay_directory(exist_ok=False) crashes with FileExistsError —
which surfaced as a 500 on POST /overlays the first time a script
overlay was created on a deployed test box.

Adds a sentinel-gated sweep in deploy-test-server.sh that lists overlay
ids in the DB, removes any directory under overlays/ whose id has no
matching row, and drops the now-unused global_overlay_cache. Mirrors the
.kernel-overlay-migrated sentinel pattern so reruns are no-ops.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

deploy/deploy-test-server.sh

@@ -203,6 +203,36 @@ if [ ! -e "$overlay_sentinel" ]; then
     $sudo_cmd chown left4me:left4me "$overlay_sentinel"
 fi
 
+# One-shot migration: 0005_script_overlays drops the legacy
+# l4d2center_maps / cedapug_maps overlay rows but doesn't touch their
+# directories under /var/lib/left4me/overlays/{id}. Without cleanup, when
+# AUTOINCREMENT (or its absence after the 0002 batch_alter_table recreate)
+# re-issues an id matching one of those orphan dirs, the web app's
+# create_overlay_directory(exist_ok=False) fails with FileExistsError.
+# Sweep any overlay dir whose id has no matching DB row, plus the
+# now-unused global_overlay_cache.
+overlay_orphan_sentinel=/var/lib/left4me/.script-overlays-orphans-cleaned
+if [ ! -e "$overlay_orphan_sentinel" ]; then
+    $sudo_cmd rm -rf /var/lib/left4me/global_overlay_cache
+    $sudo_cmd sh -c '
+        cd /var/lib/left4me/overlays || exit 0
+        ids_in_db=$(/opt/left4me/.venv/bin/python -c "
+import sqlite3
+c = sqlite3.connect(\"/var/lib/left4me/left4me.db\")
+print(\" \".join(str(r[0]) for r in c.execute(\"SELECT id FROM overlays\")))
+")
+        for d in */; do
+            id=${d%/}
+            case " $ids_in_db " in
+                *" $id "*) ;;
+                *) echo "removing orphan overlay dir: $id"; rm -rf "$id" ;;
+            esac
+        done
+    '
+    $sudo_cmd touch "$overlay_orphan_sentinel"
+    $sudo_cmd chown left4me:left4me "$overlay_orphan_sentinel"
+fi
+
 $sudo_cmd systemctl daemon-reload
 $sudo_cmd systemctl enable --now left4me-web.service
 $sudo_cmd systemctl restart left4me-web.service

deploy/tests/test_deploy_artifacts.py

@@ -277,10 +277,15 @@ def test_globals_refresh_units_removed():
     assert not GLOBAL_REFRESH_TIMER.exists()
 
 
-def test_deploy_script_does_not_reference_globals_subsystem():
+def test_deploy_script_does_not_provision_globals_subsystem():
     script = DEPLOY_SCRIPT.read_text()
 
-    assert "/var/lib/left4me/global_overlay_cache" not in script
+    # No mkdir/install of the deleted cache dir; mention in a one-shot
+    # `rm -rf` cleanup is fine.
+    for line in script.splitlines():
+        if "/var/lib/left4me/global_overlay_cache" not in line:
+            continue
+        assert "rm -rf" in line, line
     assert "left4me-refresh-global-overlays" not in script