chore(service): avoid network-online stall and speed pipenv boot

Co-authored-by: Cursor <cursoragent@cursor.com>

scripts/start.sh

@@ -1,5 +1,38 @@
 #!/usr/bin/env bash
 # Start the LED controller web server (port 80 by default).
-cd "$(dirname "$0")/.."
+# Avoid `pipenv run` on the hot path — it re-resolves the env every time and is slow on a Pi.
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+cd "$ROOT"
 export PORT="${PORT:-80}"
-pipenv run run
+export PIPENV_VENV_IN_PROJECT="${PIPENV_VENV_IN_PROJECT:-1}"
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+CACHE="$SCRIPT_DIR/.led-controller-venv"
+PYTHON=""
+
+if [ -x "$ROOT/.venv/bin/python" ]; then
+  PYTHON="$ROOT/.venv/bin/python"
+elif [ -f "$CACHE" ]; then
+  _v="$(tr -d '\r\n' < "$CACHE")"
+  if [ -n "$_v" ] && [ -x "$_v/bin/python" ]; then
+    PYTHON="$_v/bin/python"
+  fi
+fi
+
+if [ -z "$PYTHON" ] && command -v pipenv >/dev/null 2>&1; then
+  _v="$(cd "$ROOT" && pipenv --venv 2>/dev/null || true)"
+  if [ -n "${_v:-}" ] && [ -x "$_v/bin/python" ]; then
+    PYTHON="$_v/bin/python"
+    printf '%s\n' "$_v" > "$CACHE" || true
+  fi
+fi
+
+if [ -z "$PYTHON" ]; then
+  echo 'led-controller: no venv resolved; using pipenv run (slow). Run: cd '"$ROOT"' && PIPENV_VENV_IN_PROJECT=1 pipenv install --skip-lock --python "$(command -v python3)"' >&2
+  exec pipenv run run
+fi
+
+cd "$ROOT/src"
+exec "$PYTHON" -u main.py