Add business dashboard dark mode from Super Admin theme setting.

Login and in-app surfaces follow tenant themeMode, matching customer dark tokens, with themed switches and tighter card/table chrome.

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/business/src/components/MultiSelectDropdown.module.css

@@ -14,7 +14,7 @@
   font-family: inherit;
   color: var(--text-primary);
   text-align: left;
-  background: rgba(255, 255, 255, 0.65);
+  background: var(--surface);
   border: 1px solid rgba(148, 163, 184, 0.35);
   border-radius: var(--radius-sm);
   transition: border-color 0.2s, box-shadow 0.2s;
@@ -71,7 +71,7 @@
   flex-direction: column;
   max-height: none;
   overflow: visible;
-  background: rgba(255, 255, 255, 0.95);
+  background: var(--elevated-surface);
   backdrop-filter: blur(16px);
   -webkit-backdrop-filter: blur(16px);
   border: 1px solid var(--glass-border);
@@ -148,7 +148,7 @@
   border: 1.5px solid rgba(148, 163, 184, 0.55);
   border-radius: 4px;
   color: white;
-  background: white;
+  background: var(--card-media-bg);
 }
 
 .checkSelected {