Add matrixbot source to repo

All bot source files from LXC 151 (/opt/matrixbot) are now tracked here.
Secrets (.env, credentials.json), venv dirs, and runtime state files
(nio_store, welcome_state.json, wordle_stats.json) are excluded via .gitignore.
Includes deploy.sh to sync files to /opt/matrixbot and restart the service.

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

matrixbot/requirements.txt

@@ -0,0 +1,5 @@
+matrix-nio[e2e]
+python-dotenv
+aiohttp
+markdown
+mcrcon