Add LED tool: device, CLI, web UI, build scripts, and tests

- device.py: device communication/handling
- cli.py: CLI interface updates
- web.py: web interface
- build.py, build.sh, install.sh: build and install scripts
- Pipfile: Python dependencies
- lib/mpremote: mpremote library
- test_*.py: import and LED tests
- Updated .gitignore and README

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

Pipfile

@@ -0,0 +1,20 @@
+[[source]]
+url = "https://pypi.org/simple"
+verify_ssl = true
+name = "pypi"
+
+[packages]
+flask = "*"
+pyserial = "*"
+
+[dev-packages]
+pyinstaller = "*"
+
+[requires]
+python_version = "3"
+
+[scripts]
+web = "python web.py"
+cli = "python cli.py"
+build = "pyinstaller --clean led-cli.spec"
+install = "pipenv install"