Add application, Dockerfile, CI workflow and documentation

- FastAPI-based Matrix chat export tool with E2E support
- Dockerfile with Python 3.12-slim base image
- Docker Compose with dedicated network configuration
- Gitea Actions workflow for automated image builds
- README with setup instructions and feature overview
- MIT license

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

LICENSE

@@ -1,26 +1,25 @@
-GNU AFFERO GENERAL PUBLIC LICENSE
-Version 3, 19 November 2007
+MIT License
 
----
+Copyright (c) Patrick Asmus (scriptos)
 
-Copyright ©
-
-Name:    Patrick Asmus (scriptos)
-Email:   support@techniverse.net
 Website: https://www.patrick-asmus.de
 Blog:    https://www.cleveradmin.de
+Email:   support@techniverse.net
 
----
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
 
-This program is free software: you can redistribute it and/or modify
-it under the terms of the GNU Affero General Public License as published by
-the Free Software Foundation, either version 3 of the License, or
-(at your option) any later version.
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
 
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU Affero General Public License for more details.
-
-You should have received a copy of the GNU Affero General Public License
-along with this program. If not, see <https://www.gnu.org/licenses/>.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.