feat(integration): add docs/visio logos, theme.css, and nginx updates

Add SVG logos for docs and visio apps. Update drive, mail, people logos.
Add theme.css served at /api/v2/theme.css for La Suite frontend theming.
Update nginx to serve theme endpoint and tighten cache headers.
Update Dockerfile to include new static assets.

nginx.conf

@@ -26,6 +26,14 @@ server {
         add_header Cache-Control "public, max-age=86400";
     }
 
+    # v2 theme — brand CSS variable overrides served from image
+    location = /api/v2/theme.css {
+        alias /usr/share/nginx/html/theme.css;
+        add_header Content-Type "text/css; charset=utf-8";
+        add_header Access-Control-Allow-Origin "*";
+        add_header Cache-Control "public, max-age=3600";
+    }
+
     # v1 gaufre.js — thin wrapper served from image (no DOMAIN_SUFFIX needed)
     location = /api/v1/gaufre.js {
         alias /usr/share/nginx/html/gaufre.js;