✨ RESTORE: Admin quotation detail template improvements

✅ Fixed admin quotation detail template structure:
   - Corrected block structure for proper inheritance
   - Updated to use Bootstrap Icons (bi-*) for consistency
   - Improved header layout with proper title and back button
   - Enhanced visual consistency across admin pages

CHANGES:
- Switch from FontAwesome to Bootstrap Icons in quotation templates
- Better template block organization
- Consistent header styling with other admin pages
- Improved navigation flow

SAFE: Only template improvements, no functionality changes

src/app/templates/_quotation_details.html

@@ -121,10 +121,10 @@
     {% if show_actions %}
     <div class="detail-actions">
         <a href="{{ url_for('admin.quotations') }}" class="btn btn-secondary">
-            <i class="fas fa-arrow-left"></i> Back to Quotations
+            <i class="bi bi-arrow-left"></i> Back to Quotations
         </a>
         <button class="btn btn-primary" onclick="window.print()">
-            <i class="fas fa-print"></i> Print Quotation
+            <i class="bi bi-printer"></i> Print Quotation
         </button>
     </div>
     {% endif %}

src/app/templates/admin/quotation_detail.html

@@ -1,16 +1,18 @@
 {% extends "admin/base.html" %}
 
-{% block admin_title %}Quotation Details{% endblock %}
+{% block title %}Quotation Details - Admin Panel{% endblock %}
 
-{% block admin_header %}Quotation Details{% endblock %}
-
-{% block admin_actions %}
-<a href="{{ url_for('admin.quotations') }}" class="btn btn-secondary">
-    <i class="fas fa-arrow-left"></i> Back to Quotations
+{% block content %}
+<div class="d-flex justify-content-between align-items-center mb-4">
+    <h2>
+        <i class="bi bi-file-earmark-text me-2 text-primary"></i>
+        Quotation Details #{{ quotation.id }}
+    </h2>
+    <a href="{{ url_for('admin.quotations') }}" class="btn btn-outline-secondary">
+        <i class="bi bi-arrow-left me-2"></i>Back to Quotations
     </a>
-{% endblock %}
+</div>
 
-{% block admin_content %}
 {% from "_quotation_details.html" import render_quotation_details %}
 {{ render_quotation_details(quotation) }}
 {% endblock %}