fix(ci): validate cached ui dependencies

scripts/ensure-deps.sh

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+UI_DIR="$ROOT_DIR/ui"
+UI_SENTINEL="$UI_DIR/node_modules/@date-fns/tz/date/mini.js"
+
+ensure_root_deps() {
+  if [[ ! -d "$ROOT_DIR/node_modules" ]]; then
+    echo "[deps] Installing root dependencies"
+    (cd "$ROOT_DIR" && bun install --frozen-lockfile)
+  fi
+}
+
+ensure_ui_deps() {
+  if [[ -d "$UI_DIR/node_modules" && -f "$UI_SENTINEL" ]]; then
+    return
+  fi
+
+  echo "[deps] Reinstalling UI dependencies"
+  rm -rf "$UI_DIR/node_modules"
+  (cd "$UI_DIR" && bun install --frozen-lockfile)
+}
+
+ensure_root_deps
+ensure_ui_deps