Fix SDK timeout and improve text contrast

SDK Loading Improvements:
- Increased timeout from 5 to 15 seconds for slower connections
- Added progressive status messages during SDK loading
- Enhanced console logging for debugging
- Added fallback SDK loading mechanism with inline script
- Better error diagnostics showing Twilio object status

Text Contrast Fixes:
- Updated all #333 colors to #212529 for better readability
- Fixed browser phone title, dial buttons, timer, queue headings
- Enhanced dark mode support for all text elements
- Improved readability on both light and dark backgrounds

Technical Changes:
- waitForTwilioSDK() now waits 150 attempts (15 seconds)
- Progressive status updates at 3s, 6s, 10s intervals
- Backup SDK loading via document.createElement
- Comprehensive dark mode color coverage
- Better error messaging for network issues

Accessibility Improvements:
- Higher contrast ratios for WCAG compliance
- Consistent text color hierarchy
- Better visibility in all lighting conditions
- Enhanced mobile readability

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

assets/css/browser-phone-frontend.css

@@ -17,7 +17,7 @@
 .twp-browser-phone-title {
     text-align: center;
     margin: 0 0 20px 0;
-    color: #333;
+    color: #212529;
     font-size: 1.5rem;
     font-weight: 600;
 }
@@ -166,7 +166,7 @@
     padding: 16px 8px;
     font-size: 20px;
     font-weight: 600;
-    color: #333;
+    color: #212529;
     cursor: pointer;
     transition: all 0.2s ease;
     min-height: 60px;
@@ -280,7 +280,7 @@
 .timer-value {
     font-size: 18px;
     font-weight: 600;
-    color: #333;
+    color: #212529;
     font-family: 'Courier New', monospace;
 }
 
@@ -304,7 +304,7 @@
 
 .twp-queue-section h4 {
     margin: 0 0 16px 0;
-    color: #333;
+    color: #212529;
     font-size: 1.1rem;
     text-align: center;
 }
@@ -369,7 +369,7 @@
 
 .queue-name {
     font-weight: 600;
-    color: #333;
+    color: #212529;
     margin-bottom: 4px;
 }
 
@@ -410,7 +410,7 @@
 
 .selected-queue-info h5 {
     margin: 0 0 8px 0;
-    color: #333;
+    color: #212529;
     font-size: 1rem;
 }
 
@@ -592,7 +592,15 @@
     
     .queue-name,
     .status-text,
-    .twp-phone-selection label {
+    .twp-phone-selection label,
+    .twp-browser-phone-title,
+    .twp-queue-section h4,
+    .selected-queue-info h5,
+    .timer-value {
+        color: #f7fafc;
+    }
+    
+    .twp-dial-btn {
         color: #f7fafc;
     }