Initial commit: AYON Matrix Publish addon

- package.py: addon manifest (v0.1.0)
- server/__init__.py: BaseServerAddon definition
- server/ayon_matrix_publish/plugins/publish/integrate_matrix.py:
  Pyblish plugin that uploads published representations to Matrix
  rooms during the Integration stage. Supports:
  - Upload to Matrix content repository (mxc:// URI)
  - Formatted messages with preview images
  - Auto room creation per asset
  - Configurable via Studio Settings or env vars
- create_package.py: builds distributable .zip package

server/ayon_matrix_publish/version.py

@@ -0,0 +1,3 @@
+# -*- coding: utf-8 -*-
+"""Matrix Publish addon."""
+__version__ = "0.1.0"