chore(prompts): host fallback build and minimal manifest parser (no PyYAML)

scripts/prompts

@@ -31,7 +31,11 @@ build_manifest() {
   # Write on host to avoid ownership issues; container prints to stdout.
   TMP_OUT=$(mktemp)
   trap '[[ -n "${TMP_OUT:-}" ]] && rm -f "$TMP_OUT"' EXIT
-  ci_run "python3 scripts/prompt_build.py '$manifest' -" >"$TMP_OUT"
+  ci_run "python3 scripts/prompt_build.py '$manifest' -" >"$TMP_OUT" || true
+  # Fallback: if container produced no output, run on host
+  if [[ ! -s "$TMP_OUT" ]]; then
+    python3 scripts/prompt_build.py "$manifest" - >"$TMP_OUT"
+  fi
   mkdir -p "$(dirname "$out")"
   mv "$TMP_OUT" "$out"
 }