Add Windows installer packaging (Setup.exe + portable exe)

PyInstaller onedir/onefile specs, Inno Setup script, and GitHub Actions
workflow to produce JUC500-Setup-win64.exe and portable builds.

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

pyproject.toml

@@ -0,0 +1,20 @@
+[build-system]
+requires = ["setuptools>=68"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "juc500-xfer"
+version = "0.1.0"
+description = "Apple Silicon Mac ↔ Windows 11 file transfer over j5create JUC500"
+readme = "README.md"
+requires-python = ">=3.10"
+dependencies = ["pyusb>=1.2.1"]
+
+[project.scripts]
+juc500 = "juc500_xfer.cli:main"
+
+[tool.setuptools.packages.find]
+include = ["juc500_xfer*"]
+
+[tool.setuptools.package-data]
+juc500_xfer = ["static/*"]