fix: return raw rows from enhanced repository methods (refs #47)

Enhanced repository methods were incorrectly calling mapRow() which
converts snake_case to camelCase, but the service's toEnhancedResponse()
expects raw database rows with snake_case properties. This caused
"Invalid time value" errors when calling new Date(row.created_at).

Fixed methods:
- createEnhanced
- findByVehicleIdEnhanced
- findByUserIdEnhanced
- findByIdEnhanced
- getPreviousLogByOdometer
- getLatestLogForVehicle
- updateEnhanced

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

backend/src/features/fuel-logs/data/fuel-logs.repository.ts

@@ -293,7 +293,7 @@ export class FuelLogsRepository {
       data.notes ?? null
     ];
     const res = await this.pool.query(query, values);
-    return res.rows[0] ? this.mapRow(res.rows[0]) : null;
+    return res.rows[0] ?? null;
   }
 
   async findByVehicleIdEnhanced(vehicleId: string): Promise<any[]> {
@@ -301,7 +301,7 @@ export class FuelLogsRepository {
       `SELECT * FROM fuel_logs WHERE vehicle_id = $1 ORDER BY date_time DESC NULLS LAST, date DESC NULLS LAST, created_at DESC`,
       [vehicleId]
     );
-    return res.rows.map(row => this.mapRow(row));
+    return res.rows;
   }
 
   async findByUserIdEnhanced(userId: string): Promise<any[]> {
@@ -309,12 +309,12 @@ export class FuelLogsRepository {
       `SELECT * FROM fuel_logs WHERE user_id = $1 ORDER BY date_time DESC NULLS LAST, date DESC NULLS LAST, created_at DESC`,
       [userId]
     );
-    return res.rows.map(row => this.mapRow(row));
+    return res.rows;
   }
 
   async findByIdEnhanced(id: string): Promise<any | null> {
     const res = await this.pool.query(`SELECT * FROM fuel_logs WHERE id = $1`, [id]);
-    return res.rows[0] ? this.mapRow(res.rows[0]) : null;
+    return res.rows[0] ?? null;
   }
 
   async getPreviousLogByOdometer(vehicleId: string, odometerReading: number): Promise<any | null> {
@@ -322,7 +322,7 @@ export class FuelLogsRepository {
       `SELECT * FROM fuel_logs WHERE vehicle_id = $1 AND odometer IS NOT NULL AND odometer < $2 ORDER BY odometer DESC LIMIT 1`,
       [vehicleId, odometerReading]
     );
-    return res.rows[0] ? this.mapRow(res.rows[0]) : null;
+    return res.rows[0] ?? null;
   }
 
   async getLatestLogForVehicle(vehicleId: string): Promise<any | null> {
@@ -330,7 +330,7 @@ export class FuelLogsRepository {
       `SELECT * FROM fuel_logs WHERE vehicle_id = $1 ORDER BY date_time DESC NULLS LAST, date DESC NULLS LAST, created_at DESC LIMIT 1`,
       [vehicleId]
     );
-    return res.rows[0] ? this.mapRow(res.rows[0]) : null;
+    return res.rows[0] ?? null;
   }
 
   async updateEnhanced(id: string, data: {
@@ -416,6 +416,6 @@ export class FuelLogsRepository {
       return null;
     }
 
-    return this.mapRow(result.rows[0]);
+    return result.rows[0];
   }
 }