refactor: remove tour feature and Tjing import

Tour functionality has moved to its own project (HyzrTour).
Removes all tour-related code, Tjing integration, and associated
views/styles/scripts. Keeps the saveCourseToDB ON CONFLICT fix.

views/pages/courses.ejs

@@ -19,23 +19,6 @@
             </div>
         </div>
 
-        <div class="card-section">
-            <h3>Import from Tjing</h3>
-            <div class="card-section-form">
-                <input
-                    type="text"
-                    class="input"
-                    id="tjing-search"
-                    placeholder="Search Tjing by name or city..."
-                    style="width: 340px;"
-                />
-                <button class="btn" onclick="searchTjing()" id="tjing-search-btn">
-                    <i class="fas fa-search"></i> Search
-                </button>
-            </div>
-            <div id="tjing-results"></div>
-        </div>
-
         <div id="loading" class="loading" style="display: none;">Loading courses...</div>
         <div id="courses-table" hx-get="/partials/course-table" hx-trigger="load"></div>
 `; %>