Add comprehensive queue management to browser phone shortcode

Features Added:
- Queue display showing all assigned queues for the current user
- Real-time queue statistics (waiting calls, capacity)
- Visual indicators for queues with waiting calls (green border, pulse animation)
- Queue selection with click interaction
- Accept next call from selected queue functionality
- Auto-refresh of queue data every 30 seconds
- Mobile-responsive queue interface

Backend Changes:
- New ajax_get_agent_queues() handler to fetch user's assigned queues
- Enhanced ajax_get_waiting_calls() to return structured data
- Proper permission checking for twp_access_agent_queue capability

Frontend Enhancements:
- Interactive queue list with selection states
- Queue controls panel showing selected queue info
- Refresh button for manual queue updates
- Visual feedback for queues with active calls
- Mobile-optimized layout for smaller screens

UI/UX Improvements:
- Queues with waiting calls highlighted with green accent
- Pulsing indicator for active queues
- Auto-selection of first queue with calls
- Responsive design for mobile devices
- Dark mode support for queue elements

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

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

includes/class-twp-shortcodes.php

@@ -153,15 +153,31 @@ class TWP_Shortcodes {
                 </div>
             </div>
             
-            <!-- Queue Controls (for agents) -->
-            <div class="twp-queue-controls" id="twp-queue-controls" style="display: none;">
-                <h4>Queue Management</h4>
-                <div class="queue-status">
-                    <span>Waiting calls: <span id="twp-waiting-count">0</span></span>
+            <!-- Queue Management Section -->
+            <div class="twp-queue-section" id="twp-queue-section">
+                <h4>Your Queues</h4>
+                <div class="twp-queue-list" id="twp-queue-list">
+                    <div class="queue-loading">Loading queues...</div>
+                </div>
+                
+                <!-- Queue Controls -->
+                <div class="twp-queue-controls" id="twp-queue-controls" style="display: none;">
+                    <div class="selected-queue-info">
+                        <h5 id="selected-queue-name">No queue selected</h5>
+                        <div class="queue-stats">
+                            <span class="waiting-count">Waiting: <span id="twp-waiting-count">0</span></span>
+                            <span class="queue-size">Max: <span id="twp-queue-max-size">-</span></span>
+                        </div>
+                    </div>
+                    <div class="queue-actions">
+                        <button id="twp-accept-queue-call" class="twp-btn twp-btn-success">
+                            Accept Next Call
+                        </button>
+                        <button id="twp-refresh-queues" class="twp-btn twp-btn-secondary">
+                            Refresh
+                        </button>
+                    </div>
                 </div>
-                <button id="twp-accept-queue-call" class="twp-btn twp-btn-success">
-                    Accept Next Call
-                </button>
             </div>
             
             <!-- Audio elements -->