Fix: link share_id to geo_id so /watch returns correct position

bin/database/database_provider.dart

@@ -12,7 +12,7 @@ import '../models/log.dart';
 class DatabaseProvider {
   late Connection _dbConnection;
 
-  final Map<String, bool> _shareLinks = {};
+  final Map<String, String> _shareLinks = {};
   final _uuid = const Uuid();
 
   Future<void> initialize() async {
@@ -284,6 +284,28 @@ Future<Geoposition?> getLatestPosition() async {
     );
   }
 
+  Future<Geoposition?> getPositionById(String id) async {
+    final results = await _dbConnection.execute(
+      Sql.named('''
+      SELECT id, x_value, y_value, last_update, expires_at
+      FROM geopositions
+      WHERE id = @id AND expires_at > NOW()
+      '''),
+      parameters: {'id': id},
+    );
+
+    if (results.isEmpty) return null;
+
+    final row = results.first;
+    return Geoposition(
+      id: row[0].toString(),
+      xValue: double.parse(row[1].toString()),
+      yValue: double.parse(row[2].toString()),
+      lastUpdate: DateTime.parse(row[3].toString()),
+      expiresAt: DateTime.parse(row[4].toString()),
+    );
+  }
+
   Future<void> cleanupExpired() async {
     await _dbConnection.execute(
       Sql.named('DELETE FROM geopositions WHERE expires_at < NOW()'),
@@ -292,14 +314,14 @@ Future<Geoposition?> getLatestPosition() async {
 
   // ==================== Share operations ====================
 
-  String createShareId() {
+  String createShareId(String geoId) {
     final uniqueId = _uuid.v4();
-    _shareLinks[uniqueId] = true;
+    _shareLinks[uniqueId] = geoId;
     return uniqueId;
   }
 
-  bool isValidShareId(String uniqueId) {
-    return _shareLinks[uniqueId] == true;
+  String? getGeoIdByShareId(String uniqueId) {
+    return _shareLinks[uniqueId];
   }
 
   // ==================== Log operations ====================