ci: add auto-deploy to S1+S2 via rsync after merge to main

Adds new "deploy" job in .gitea/workflows/ci.yml that runs on push
to main (after PR is merged). Builds production bundle and rsyncs
it to /var/www/rublox-studio/build/ on both production servers
(S1 VM 124 via NAT 1998, S2 VM 124 directly via runner network).

Uses Gitea Secrets:
  - DEPLOY_SSH_KEY: dedicated ed25519 key for CI, pubkey already
    on ~min/.ssh/authorized_keys on both VM 124
  - KNOWN_HOSTS: host-keys of both targets to prevent MITM

Also updates CONTRIBUTING.md:
  - Maintainer workflow section explaining why even Lead works via PR
  - Hotfix flow (always via PR, never direct push to main)
  - DevPanel as fallback if CI deploy is broken

src/editor/Icon.jsx

@@ -313,7 +313,7 @@ const EMOJI_TO_NAME = {
   '◣': 'prim-wedge', '◢': 'prim-cornerwedge', '〰': 'waves',
   // UI / художественные
   '🎨': 'palette', '📺': 'monitor', '🖼': 'image', '🖼️': 'image',
-  '🔤': 'type',
+  '🔤': 'type', '🟧': 'square',
   // звук
   '🎵': 'music', '🎼': 'music2', '🔊': 'sound',
   // навигация