feat: add ESP-IDF setup and build helper scripts

Signed-off-by: Asklv <boironic@gmail.com>

scripts/build_ubuntu.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+PROJECT_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+IDF_VERSION="${IDF_VERSION:-v5.5.2}"
+ESP_ROOT="${ESP_ROOT:-$HOME/.espressif}"
+DEFAULT_IDF_DIR="$ESP_ROOT/esp-idf-$IDF_VERSION"
+IDF_DIR="${IDF_DIR:-${IDF_PATH:-$DEFAULT_IDF_DIR}}"
+
+if [[ ! -f "$IDF_DIR/export.sh" ]]; then
+  echo "ESP-IDF not found at: $IDF_DIR" >&2
+  echo "Run scripts/setup_idf_ubuntu.sh first, or set IDF_DIR/IDF_PATH." >&2
+  exit 1
+fi
+
+# shellcheck source=/dev/null
+. "$IDF_DIR/export.sh"
+
+cd "$PROJECT_ROOT"
+idf.py set-target esp32s3
+idf.py build