Rewrite self-hosting docs and deploy script

The self-hosting documentation has been fully rewritten to match the actual deploy flow, and the deploy script now auto-generates a .env template on first run.

• Rewrote self-hosting docs to cover the real deploy flow end-to-end
• Deploy script auto-generates .env template when missing, instead of failing silently
• Added documentation for license management, air-gapped activation, and Orbit monitoring
• Merged Admin and Enterprise sidebar sections for clearer navigation
• Fixed license refresh endpoint that caused 500 errors during validation
• Fixed station duplicate check and limit-reached modal