Add Autodesk cloud sync connector

Initial implementation of the ifcviewer-autodesk connector — a separate process that bridges the IfcViewer to Autodesk APS (BIM 360 / ACC). Speaks JSON-RPC 2.0 over stdio per CLOUD_SYNC_PROTOCOL.md (also added). PKCE OAuth with keyring-backed token storage, customtkinter browse/picker UI, and PyInstaller packaging.

Implements both interactive and non-interactive variants of each push/pull (pull_ifcfed[_interactive], pull_models[_interactive], push_ifcfed[_interactive], push_model[_interactive]) so the viewer can offer both "Save"/"Open from Cloud" and "Save As"/"Add Model from Cloud" entry points. File transfers report progress through a dialog with per-byte updates; pull_models shows "(i/N)" for batches.

Generated with the assistance of an AI coding tool.

src/ifcviewer-autodesk/pyproject.toml

@@ -0,0 +1,27 @@
+[build-system]
+requires = ["setuptools>=69", "wheel"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "ifcviewer-autodesk"
+version = "0.1.0"
+description = "Autodesk cloud connector for IfcViewer"
+readme = "README.md"
+requires-python = ">=3.11"
+dependencies = [
+  "customtkinter>=5.2",
+  "httpx>=0.27",
+  "keyring>=25.2"
+]
+
+[project.optional-dependencies]
+build = ["pyinstaller>=6.0"]
+
+[tool.setuptools]
+include-package-data = true
+
+[tool.setuptools.packages.find]
+where = ["."]
+
+[project.scripts]
+ifcviewer-autodesk = "ifcviewer_autodesk.__main__:main"