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.

public/css/courses.css

@@ -132,36 +132,3 @@
     border-style: dashed;
 }
 
-/* ── Tjing Import ────────────────────────────── */
-
-.tjing-result {
-    display: flex;
-    justify-content: space-between;
-    align-items: center;
-    padding: 12px 14px;
-    margin: 6px 0;
-    background: var(--surface-2);
-    border-radius: var(--radius-sm);
-    border: 1px solid var(--border);
-}
-
-.tjing-result-info {
-    display: flex;
-    flex-direction: column;
-    gap: 2px;
-}
-
-.tjing-result-name {
-    font-weight: 600;
-    font-size: 14px;
-    color: var(--text-primary);
-}
-
-.tjing-result-address {
-    font-size: 13px;
-    color: var(--text-secondary);
-}
-
-#tjing-results {
-    margin-top: 12px;
-}