Add pagination to QSO Log and back buttons to pages

- Add backend pagination support for /api/qsos endpoint (page, limit params)
- Return paginated results with metadata (totalCount, totalPages, hasNext, hasPrev)
- Add pagination UI to QSOs page with prev/next buttons and page numbers
- Add back button to QSO Log and Settings pages linking to main menu
- Reset to page 1 when applying filters

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/backend/services/lotw.service.js

@@ -468,15 +468,18 @@ export async function syncQSOs(userId, lotwUsername, lotwPassword, sinceDate = n
 }
 
 /**
- * Get QSOs for a user
+ * Get QSOs for a user with pagination
  * @param {number} userId - User ID
  * @param {Object} filters - Query filters
- * @returns {Promise<Array>} Array of QSOs
+ * @param {Object} options - Pagination options { page, limit }
+ * @returns {Promise<Object>} Paginated QSOs
  */
-export async function getUserQSOs(userId, filters = {}) {
-  const { eq, and } = await import('drizzle-orm');
+export async function getUserQSOs(userId, filters = {}, options = {}) {
+  const { eq, and, desc, sql } = await import('drizzle-orm');
 
-  console.error('getUserQSOs called with userId:', userId, 'filters:', filters);
+  const { page = 1, limit = 100 } = options;
+
+  console.error('getUserQSOs called with userId:', userId, 'filters:', filters, 'page:', page, 'limit:', limit);
 
   // Build where conditions
   const conditions = [eq(qsos.userId, userId)];
@@ -493,17 +496,35 @@ export async function getUserQSOs(userId, filters = {}) {
     conditions.push(eq(qsos.lotwQslRstatus, 'Y'));
   }
 
-  // Use and() to combine all conditions
-  const results = await db.select().from(qsos).where(and(...conditions));
+  // Get total count for pagination
+  const allResults = await db.select().from(qsos).where(and(...conditions));
+  const totalCount = allResults.length;
 
-  console.error('getUserQSOs returning', results.length, 'QSOs');
+  // Calculate offset
+  const offset = (page - 1) * limit;
 
-  // Order by date descending, then time
-  return results.sort((a, b) => {
-    const dateCompare = b.qsoDate.localeCompare(a.qsoDate);
-    if (dateCompare !== 0) return dateCompare;
-    return b.timeOn.localeCompare(a.timeOn);
-  });
+  // Get paginated results
+  const results = await db
+    .select()
+    .from(qsos)
+    .where(and(...conditions))
+    .orderBy(desc(qsos.qsoDate), desc(qsos.timeOn))
+    .limit(limit)
+    .offset(offset);
+
+  console.error('getUserQSOs returning', results.length, 'QSOs (page', page, 'of', Math.ceil(totalCount / limit), ')');
+
+  return {
+    qsos: results,
+    pagination: {
+      page,
+      limit,
+      totalCount,
+      totalPages: Math.ceil(totalCount / limit),
+      hasNext: page * limit < totalCount,
+      hasPrev: page > 1,
+    },
+  };
 }
 
 /**