feat(02-02): implement ESP32Transport UDP client with asyncio DatagramProtocol

- ESP32Transport.send_command() injects v:1, fire-and-forget, silent drop if not ready
- 512-byte payload limit enforced with warning log
- datagram_received() parses STATUS ok → connected=True, stores last_status
- on_status callback support for status update notifications
- connection_lost() sets connected=False, clears transport ref
- create_esp32_transport() async factory sends initial STATUS ping (D-12)
- All protocol behaviors match docs/protocol.md exactly (D-10, D-11, D-12, D-14)
- Add pytest-asyncio to dev deps + asyncio_mode=auto for test suite

tests/test_scaffold.py

@@ -0,0 +1,33 @@
+"""TDD RED: Tests for project scaffold — these must fail before implementation."""
+import subprocess
+import sys
+
+
+def test_led_sync_importable():
+    """led_sync package must be importable with a __version__ attribute."""
+    result = subprocess.run(
+        ["uv", "run", "python", "-c", "import led_sync; print(led_sync.__version__)"],
+        capture_output=True,
+        text=True,
+        cwd="/home/claude/keineahnungirgendeintesthalt",
+    )
+    assert result.returncode == 0, f"Import failed: {result.stderr}"
+    assert result.stdout.strip(), "No version printed"
+
+
+def test_core_dependencies_importable():
+    """All Phase 2 core deps must be importable."""
+    result = subprocess.run(
+        [
+            "uv",
+            "run",
+            "python",
+            "-c",
+            "import miniaudio, sounddevice, numpy, pydantic; print('OK')",
+        ],
+        capture_output=True,
+        text=True,
+        cwd="/home/claude/keineahnungirgendeintesthalt",
+    )
+    assert result.returncode == 0, f"Dependency import failed: {result.stderr}"
+    assert "OK" in result.stdout