fix(docker): make the site icon configurable at runtime

Add SITE_ICON_FILE and SITE_ICON_URL support for the Docker image, route the app shell and manifest through a runtime icon endpoint, document the new Docker branding flow, and bump the app version to 4.8.3.

components/layout/Navbar.tsx

@@ -5,7 +5,7 @@ import Link from 'next/link';
 import Image from 'next/image';
 import { ThemeSwitcher } from '@/components/ThemeSwitcher';
 import { Icons } from '@/components/ui/Icon';
-import { siteConfig } from '@/lib/config/site-config';
+import { siteConfig, SITE_ICON_PATH } from '@/lib/config/site-config';
 import { getSession, clearSession, hasPermission, type AuthSession } from '@/lib/store/auth-store';
 import { useRuntimeFeatures } from '@/components/RuntimeFeaturesProvider';
 import { LogOut } from 'lucide-react';
@@ -45,10 +45,11 @@ export function Navbar({ onReset, isPremiumMode = false }: NavbarProps) {
                         >
                             <div className="w-8 h-8 sm:w-10 sm:h-10 relative flex items-center justify-center flex-shrink-0">
                                 <Image
-                                    src="/icon.png"
+                                    src={SITE_ICON_PATH}
                                     alt={siteConfig.name}
                                     width={40}
                                     height={40}
+                                    unoptimized
                                     className="object-contain"
                                 />
                             </div>

components/player/PlayerNavbar.tsx

@@ -4,7 +4,7 @@ import Image from 'next/image';
 import { Button } from '@/components/ui/Button';
 import { ThemeSwitcher } from '@/components/ThemeSwitcher';
 import { Icons } from '@/components/ui/Icon';
-import { siteConfig } from '@/lib/config/site-config';
+import { siteConfig, SITE_ICON_PATH } from '@/lib/config/site-config';
 
 export function PlayerNavbar({ isPremium }: { isPremium?: boolean }) {
     const router = useRouter();
@@ -20,10 +20,11 @@ export function PlayerNavbar({ isPremium }: { isPremium?: boolean }) {
                             title={isPremium ? "返回高级主页" : "返回首页"}
                         >
                             <Image
-                                src="/icon.png"
+                                src={SITE_ICON_PATH}
                                 alt={siteConfig.name}
                                 width={40}
                                 height={40}
+                                unoptimized
                                 className="object-contain"
                             />
                         </button>