restore green-wash theme (lost in the Oct 21 rebuild) + PWA band colors

The Oct 19 theming (light = #eaf3ea dashboard green wash, white cards/surfaces,
per approval) was never committed - the Oct 21 pin-migration rebuild from this
repo silently reverted the deployed theme to the older cream iteration.

- custom.css: light block restored to the approved green-wash palette
  (primary #eaf3ea, white secondary/chat cards, green hover/tertiary/border);
  loading screen + bare page background match.
- Dockerfile: manifest theme_color/background_color and the index.html
  theme-color media pair now follow the live palette (#eaf3ea light /
  #22271f deep pine dark).
- custom2.js: sync ONE meta theme-color to the app's resolved theme
  (html.dark class + prefers-color-scheme listener) so Android status/nav
  bands and iOS safe areas track the theme at runtime; the static media
  pair remains as the no-JS fallback.

assets/custom2.js

@@ -39,9 +39,44 @@
       ' · Our AI, governed together';
   }
 
+  // PWA chrome bands (Android status bar + navigation bar, iOS safe areas):
+  // LibreChat ships static meta theme-color tags and never updates them, so
+  // the OS bands keep the install-time colors. Sync ONE meta tag to the app's
+  // RESOLVED theme (html.dark class — LibreChat applies it from the user's
+  // theme setting, which defaults to system = the phone's theme). Falls back
+  // to the light/dark media-query pair in index.html when this script is off.
+  var COOP_BG = { light: '#eaf3ea', dark: '#22271f' };
+  function syncThemeColor() {
+    var dark = document.documentElement.classList.contains('dark');
+    var metas = document.querySelectorAll('meta[name="theme-color"]');
+    if (!metas.length) return;
+    // Replace the media-query pair with a single tag at the resolved color.
+    metas.forEach(function (m, i) {
+      if (i === 0) {
+        m.removeAttribute('media');
+        m.setAttribute('content', dark ? COOP_BG.dark : COOP_BG.light);
+      } else {
+        m.remove();
+      }
+    });
+  }
+  var themeObserverRunning = false;
+  function startThemeSync() {
+    if (themeObserverRunning) return;
+    themeObserverRunning = true;
+    syncThemeColor();
+    new MutationObserver(syncThemeColor).observe(document.documentElement, {
+      attributes: true,
+      attributeFilter: ['class'],
+    });
+    var mq = window.matchMedia('(prefers-color-scheme: dark)');
+    if (mq && mq.addEventListener) mq.addEventListener('change', syncThemeColor);
+  }
+
   function run() {
     hideSignupPrompt();
     fixFooter();
+    startThemeSync();
   }
 
   function start() {