fix: Replace Pro theme tokens with literal colors

The two-factor stylesheets were carried over from the Pro edition and
referenced CSS custom properties from its theme system, which this
edition does not define. They silently fell back to browser defaults.

client/src/components/common/Login/TotpChallengeModal.module.scss

@@ -5,7 +5,7 @@
 
 :global(#app) {
   .intro {
-    color: var(--text-secondary);
+    color: #444444;
     margin-bottom: 16px;
   }
 

client/src/components/users/UserSettingsModal/SecurityPane/RecoveryCodesView.module.scss

@@ -5,8 +5,8 @@
 
 :global(#app) {
   .wrapper {
-    background: var(--surface-raised);
-    border: 1px solid var(--grey-e0e0e0);
+    background: #fafafa;
+    border: 1px solid #e0e0e0;
     border-radius: 6px;
     padding: 12px;
   }

client/src/components/users/UserSettingsModal/SecurityPane/SecurityPane.module.scss

@@ -10,12 +10,12 @@
   }
 
   .intro {
-    color: var(--text-secondary);
+    color: #444444;
     margin-bottom: 16px;
   }
 
   .enabledMeta {
-    color: var(--text-secondary);
+    color: #444444;
     font-weight: normal;
   }
 

client/src/components/users/UserSettingsModal/SecurityPane/TotpSetupWizard.module.scss

@@ -5,7 +5,7 @@
 
 :global(#app) {
   .intro {
-    color: var(--text-secondary);
+    color: #444444;
     margin-bottom: 12px;
   }
 
@@ -14,8 +14,8 @@
   }
 
   .qrWrapper {
-    background: var(--surface-card);
-    border: 1px solid var(--grey-dddddd);
+    background: #ffffff;
+    border: 1px solid #dddddd;
     border-radius: 8px;
     display: inline-block;
     margin: 16px 0;
@@ -23,14 +23,14 @@
   }
 
   .secretLabel {
-    color: var(--text-secondary);
+    color: #444444;
     font-size: 13px;
     margin-bottom: 6px;
   }
 
   .secret {
-    background: var(--surface-subtle);
-    border: 1px solid var(--grey-dddddd);
+    background: #f8f8f8;
+    border: 1px solid #dddddd;
     border-radius: 4px;
     display: inline-block;
     font-family: 'JetBrains Mono', 'Menlo', 'Courier New', monospace;

client/src/components/users/UserSettingsModal/SecurityPane/TrustedDevicesSection.module.scss

@@ -13,7 +13,7 @@
   }
 
   .hint {
-    color: var(--text-tertiary);
+    color: #666666;
     margin-bottom: 12px;
   }
 
@@ -32,13 +32,13 @@
   }
 
   .deviceSecondary {
-    color: var(--text-secondary) !important;
+    color: #444444 !important;
     font-size: 13px;
     margin-top: 2px !important;
   }
 
   .meta {
-    color: var(--text-tertiary) !important;
+    color: #666666 !important;
     font-size: 12px;
     margin-top: 4px;
   }