feat: donation banner, About tab, settings UI improvements

- Dismissible donation/open-source banner after 3+ sessions (30-day snooze)
- New About tab in Settings: version, repo link, license info
- Centralize project URLs (REPO_URL, DONATE_URL) in __init__.py, served via /health
- Center settings tab bar, reduce tab padding for 6-tab fit
- External URL save button: icon button instead of full-width text button
- Remove redundant settings footer close button
- Footer "Source Code" link replaced with "About" opening settings
- i18n keys for en/ru/zh

server/src/wled_controller/static/js/app.ts

@@ -8,7 +8,7 @@ import { Modal } from './core/modal.ts';
 import { queryEl } from './core/dom-utils.ts';
 
 // Layer 1: api, i18n
-import { loadServerInfo, loadDisplays, configureApiKey, startConnectionMonitor, stopConnectionMonitor } from './core/api.ts';
+import { loadServerInfo, loadDisplays, configureApiKey, startConnectionMonitor, stopConnectionMonitor, serverRepoUrl, serverDonateUrl } from './core/api.ts';
 import { t, initLocale, changeLocale } from './core/i18n.ts';
 
 // Layer 1.5: visual effects
@@ -205,6 +205,9 @@ import {
     initUpdateSettingsPanel, applyUpdate,
     openReleaseNotes, closeReleaseNotes,
 } from './features/update.ts';
+import {
+    initDonationBanner, dismissDonation, snoozeDonation, renderAboutPanel, setProjectUrls,
+} from './features/donation.ts';
 
 // ─── Register all HTML onclick / onchange / onfocus globals ───
 
@@ -576,6 +579,11 @@ Object.assign(window, {
     openReleaseNotes,
     closeReleaseNotes,
 
+    // donation
+    dismissDonation,
+    snoozeDonation,
+    renderAboutPanel,
+
     // appearance
     applyStylePreset,
     applyBgEffect,
@@ -723,6 +731,10 @@ document.addEventListener('DOMContentLoaded', async () => {
     initUpdateListener();
     loadUpdateStatus();
 
+    // Show donation banner (after a few sessions)
+    setProjectUrls(serverRepoUrl, serverDonateUrl);
+    initDonationBanner();
+
     // Show getting-started tutorial on first visit
     if (!localStorage.getItem('tour_completed')) {
         setTimeout(() => startGettingStartedTutorial(), 600);