Security: Remove generated cloud-init file with hardcoded Tailscale key

- Remove .graphdone-cloud-init.yml from git tracking (contains expired auth key)
- Add to .gitignore to prevent future commits
- This file is generated dynamically by multipass.sh from .env
- No active keys compromised (key was already expired)

Author: mvalancy

.gitignore

@@ -43,6 +43,7 @@ lerna-debug.log*
 /tmp/graphdone-cloud-init.yml
 cloud-init.*.yml
 !cloud-init.template.yml
+.graphdone-cloud-init.yml
 
 # IDE
 .vscode/*