Refresh login screen with server list UI and refactor platform config

Redesign login view with server card list, add/edit/delete modals,
and per-server ping status display. Rename ProxyOverrides to ClientConfig,
remove ConfigSystemInterface in favor of direct platform methods
(load_config, load_username, set_default_username, load_server_url),
remove SharedState threading in favor of global STATE, simplify
network_loop and audio setup, update proxy endpoint from /overrides
to /config, and clean up desktop launch configuration.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docker/Caddyfile

@@ -1,12 +1,14 @@
 localhost:64444 {
-	tls internal
+    tls internal
 
-	# Proxy /config path to mumble-web2-proxy
-	reverse_proxy /overrides http://127.0.0.1:4400
+    # Proxy /config path to mumble-web2-proxy
+    reverse_proxy /config http://127.0.0.1:4400
 
-	# Proxy /status path to mumble-web2-proxy
-	reverse_proxy /status http://127.0.0.1:4400
+    # Proxy /status path to mumble-web2-proxy
+    reverse_proxy /status http://127.0.0.1:4400
+
+
+    # Proxy root path to dx-serve
+    reverse_proxy http://127.0.0.1:8080
 
-	# Proxy root path to dx-serve
-	reverse_proxy http://127.0.0.1:8080
 }