chore(config,admin,api): Update default accent color to white and add PORT environment variable

- Change default accent color from #00D4AA (teal) to #FFFFFF (white) across all components
- Update AccentColorContext default state to use white accent color
- Update admin page form defaults and placeholders to reflect new accent color
- Update node API endpoint default accent color response
- Add optional PORT environment variable configuration to .env.example with default value of 3000
- Standardize branding color scheme for consistency across the application

src/app/admin/page.tsx

@@ -69,7 +69,7 @@ export default function AdminPage() {
         rules: '',
         bannerUrl: '',
         logoUrl: '',
-        accentColor: '#00D4AA',
+        accentColor: '#FFFFFF',
         isNsfw: false,
     });
     const [savingSettings, setSavingSettings] = useState(false);
@@ -136,7 +136,7 @@ export default function AdminPage() {
                 rules: data.rules || '',
                 bannerUrl: data.bannerUrl || '',
                 logoUrl: data.logoUrl || '',
-                accentColor: data.accentColor || '#00D4AA',
+                accentColor: data.accentColor || '#FFFFFF',
                 isNsfw: data.isNsfw || false,
             });
         } catch {
@@ -626,7 +626,7 @@ export default function AdminPage() {
                                         className="input"
                                         value={nodeSettings.accentColor}
                                         onChange={(e) => setNodeSettings({ ...nodeSettings, accentColor: e.target.value })}
-                                        placeholder="#00D4AA"
+                                        placeholder="#FFFFFF"
                                     />
                                 </div>
                             </div>

src/app/api/node/route.ts

@@ -35,7 +35,7 @@ export async function GET() {
             return NextResponse.json({
                 name: process.env.NEXT_PUBLIC_NODE_NAME || 'Synapsis Node',
                 description: process.env.NEXT_PUBLIC_NODE_DESCRIPTION || 'A federated social network node.',
-                accentColor: process.env.NEXT_PUBLIC_ACCENT_COLOR || '#00D4AA',
+                accentColor: process.env.NEXT_PUBLIC_ACCENT_COLOR || '#FFFFFF',
                 domain,
                 admins,
             });

src/lib/contexts/AccentColorContext.tsx

@@ -33,7 +33,7 @@ function applyAccentColor(color: string) {
 }
 
 export function AccentColorProvider({ children }: { children: ReactNode }) {
-    const [accentColor, setAccentColor] = useState('#00D4AA');
+    const [accentColor, setAccentColor] = useState('#FFFFFF');
 
     const refreshAccentColor = useCallback(() => {
         fetch('/api/node', { cache: 'no-store' })