Add UI Customization Panel with full color theming

- New "Interfaccia" panel with color picker (HSV + hex/RGB/alpha + 30 presets)
- Profile background customization tab
- Accent color propagates via CSS variables to: card headers/tabs,
  context menus, Button dark/primary/gray variants, InfoStand panels,
  toolbar, room tools, purse, .btn-primary/.btn-dark CSS classes
- All elements use var(--name, fallback) for zero visual change when default
- Settings persisted in localStorage
- Added react-colorful dependency
- Added ui-config.json with header images config keys

src/components/MainView.tsx

@@ -9,6 +9,7 @@ import { CampaignView } from './campaign/CampaignView';
 import { CatalogView } from './catalog/CatalogView';
 import { ChatHistoryView } from './chat-history/ChatHistoryView';
 import { FloorplanEditorView } from './floorplan-editor/FloorplanEditorView';
+import { FurniEditorView } from './furni-editor/FurniEditorView';
 import { FriendsView } from './friends/FriendsView';
 import { GameCenterView } from './game-center/GameCenterView';
 import { GroupsView } from './groups/GroupsView';
@@ -21,10 +22,12 @@ import { ModToolsView } from './mod-tools/ModToolsView';
 import { NavigatorView } from './navigator/NavigatorView';
 import { NitrobubbleHiddenView } from './nitrobubblehidden/NitrobubbleHiddenView';
 import { NitropediaView } from './nitropedia/NitropediaView';
+import { ExternalPluginLoader } from './plugins/ExternalPluginLoader';
 import { RightSideView } from './right-side/RightSideView';
 import { RoomView } from './room/RoomView';
 import { ToolbarView } from './toolbar/ToolbarView';
 import { UserProfileView } from './user-profile/UserProfileView';
+import { InterfaceSettingsView } from './interface-settings/InterfaceSettingsView';
 import { UserSettingsView } from './user-settings/UserSettingsView';
 import { WiredView } from './wired/WiredView';
 import { YoutubeTvView } from './youtube-tv/YoutubeTvView';
@@ -85,6 +88,7 @@ export const MainView: FC<{}> = props =>
             <AnimatePresence>
                 { landingViewVisible &&
                     <motion.div
+                        className="w-full h-full"
                         initial={ { opacity: 0 }}
                         animate={ { opacity: 1 }}
                         exit={ { opacity: 0 }}>
@@ -105,6 +109,7 @@ export const MainView: FC<{}> = props =>
             <FriendsView />
             <RightSideView />
             <UserSettingsView />
+            <InterfaceSettingsView />
             <UserProfileView />
             <GroupsView />
             <CameraWidgetView />
@@ -115,7 +120,9 @@ export const MainView: FC<{}> = props =>
             <CampaignView />
             <GameCenterView />
             <FloorplanEditorView />
+            <FurniEditorView />
             <YoutubeTvView />
+            <ExternalPluginLoader />
         </>
     );
 };