feat: implement Mattermost proxy mirror with configuration and scripts for capturing traffic

.gitignore

@@ -11,6 +11,8 @@ __pycache__/
 ai/inbox/mattermost-latest.md
 ai/inbox/mattermost-*.md
 ai/inbox/mattermost-status.json
+ai/inbox/mattermost-mirror/*
+!ai/inbox/mattermost-mirror/.gitkeep
 ai/inbox/photos/*
 !ai/inbox/photos/.gitkeep
 
@@ -23,6 +25,7 @@ scripts/mattermost/.env
 scripts/mattermost/.venv/
 scripts/mattermost/generated/*
 !scripts/mattermost/generated/.gitkeep
+scripts/mattermost-proxy/.env
 
 # Obsidian local runtime state
 /.obsidian/