Add comprehensive documentation and LoTW integration

- Add detailed documentation covering architecture, components, code structure
- Document award system with multiple examples (DXCC, WAS, VUCC, Satellite)
- Implement LoTW sync service with ADIF parsing and long-polling
- Add QSO logbook page with filtering and statistics
- Add settings page for LoTW credentials management
- Add API endpoints for LoTW sync, QSO retrieval, and statistics

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

src/backend/index.js

@@ -8,6 +8,11 @@ import {
   getUserById,
   updateLoTWCredentials,
 } from './services/auth.service.js';
+import {
+  syncQSOs,
+  getUserQSOs,
+  getQSOStats,
+} from './services/lotw.service.js';
 
 /**
  * Main backend application
@@ -179,7 +184,17 @@ const app = new Elysia()
       }
 
       try {
-        await updateLoTWCredentials(user.id, body.lotwUsername, body.lotwPassword);
+        // Get current user data to preserve password if not provided
+        const userData = await getUserById(user.id);
+        if (!userData) {
+          set.status = 404;
+          return { success: false, error: 'User not found' };
+        }
+
+        // If password is empty, keep existing password
+        const lotwPassword = body.lotwPassword || userData.lotwPassword;
+
+        await updateLoTWCredentials(user.id, body.lotwUsername, lotwPassword);
 
         return {
           success: true,
@@ -196,11 +211,106 @@ const app = new Elysia()
     {
       body: t.Object({
         lotwUsername: t.String(),
-        lotwPassword: t.String(),
+        lotwPassword: t.Optional(t.String()),
       }),
     }
   )
 
+  /**
+   * POST /api/lotw/sync
+   * Sync QSOs from LoTW (requires authentication)
+   */
+  .post('/api/lotw/sync', async ({ user, set }) => {
+    if (!user) {
+      set.status = 401;
+      return { success: false, error: 'Unauthorized' };
+    }
+
+    try {
+      // Get user's LoTW credentials from database
+      const userData = await getUserById(user.id);
+      if (!userData || !userData.lotwUsername || !userData.lotwPassword) {
+        set.status = 400;
+        return {
+          success: false,
+          error: 'LoTW credentials not configured. Please add them in Settings.',
+        };
+      }
+
+      // Decrypt password (for now, assuming it's stored as-is. TODO: implement encryption)
+      const lotwPassword = userData.lotwPassword;
+
+      // Sync QSOs from LoTW
+      const result = await syncQSOs(user.id, userData.lotwUsername, lotwPassword);
+
+      return result;
+    } catch (error) {
+      set.status = 500;
+      return {
+        success: false,
+        error: `LoTW sync failed: ${error.message}`,
+      };
+    }
+  })
+
+  /**
+   * GET /api/qsos
+   * Get user's QSOs (requires authentication)
+   */
+  .get('/api/qsos', async ({ user, query, set }) => {
+    if (!user) {
+      set.status = 401;
+      return { success: false, error: 'Unauthorized' };
+    }
+
+    try {
+      const filters = {};
+      if (query.band) filters.band = query.band;
+      if (query.mode) filters.mode = query.mode;
+      if (query.confirmed) filters.confirmed = query.confirmed === 'true';
+
+      const qsos = await getUserQSOs(user.id, filters);
+
+      return {
+        success: true,
+        qsos,
+        count: qsos.length,
+      };
+    } catch (error) {
+      set.status = 500;
+      return {
+        success: false,
+        error: 'Failed to fetch QSOs',
+      };
+    }
+  })
+
+  /**
+   * GET /api/qsos/stats
+   * Get QSO statistics (requires authentication)
+   */
+  .get('/api/qsos/stats', async ({ user, set }) => {
+    if (!user) {
+      set.status = 401;
+      return { success: false, error: 'Unauthorized' };
+    }
+
+    try {
+      const stats = await getQSOStats(user.id);
+
+      return {
+        success: true,
+        stats,
+      };
+    } catch (error) {
+      set.status = 500;
+      return {
+        success: false,
+        error: 'Failed to fetch statistics',
+      };
+    }
+  })
+
   // Health check endpoint
   .get('/api/health', () => ({
     status: 'ok',