Implement SSH passthrough mode and refactor Gitea domain configuration

Major Changes:
- Add dual SSH mode system (passthrough default, dedicated fallback)
- Refactor domain configuration to use direct specification pattern
- Fix critical fail2ban security gap in dedicated mode
- Separate HTTP and SSH domains for cleaner Git URLs

now-what.md

@@ -12,8 +12,8 @@
     - [ ] Contacts and calendars
     - [ ] Storage bucket integration?
 
-- [ ] Gitea
-    - [ ] SSH setup
+- [x] Gitea
+    - [x] SSH passthrough setup
 
 - [ ] Authentik Invitations for users?