Add Complete Game Progression System

MAJOR UPDATE - Full game systems based on APK analysis:

CAR SYSTEM:
- Purchase cars with Gold or Cash
- 5 starter cars across all classes (C,B,A,S,R)
- Car database with manufacturers and performance ratings
- Garage management and inventory tracking

UPGRADE SYSTEM:
- 5 upgrade types (Engine, Tires, Suspension, Brakes, Drivetrain)
- Progressive Performance Rating increases
- Cash-based upgrade economy
- Per-car upgrade tracking

PROGRESSION SYSTEM:
- Experience Points and leveling (1000 XP per level)
- Level-up rewards (10 Gold + 5K Cash)
- Reputation tracking
- Complete player profile management

CAREER MODE:
- Career series and event tracking
- Star rating system (1-3 stars per event)
- Best time tracking
- Star-based rewards (10G/2KC/100XP per star)

ECONOMY:
- Balanced F2P progression
- ~350 Gold + \ daily earning potential
- Fair pricing for cars and upgrades
- Multiple currency sources

NEW ENDPOINTS:
- GET /synergy/progression/player/{id} - Player profile
- POST /synergy/progression/player/{id}/update - Update stats
- POST /synergy/progression/car/purchase - Buy cars
- POST /synergy/progression/car/upgrade - Upgrade cars
- POST /synergy/progression/career/complete - Finish events

DATABASE:
- Cars table - Vehicle catalog
- OwnedCars table - Player garage
- CarUpgrades table - Upgrade options
- CareerProgress table - Event completion
- User table extended with Level/XP/Reputation

SEEDED DATA:
- 5 cars (Nissan Silvia to McLaren P1 GTR)
- 5 upgrades for starter car
- Time trials and gold packages from previous update

This creates a COMPLETE single-player experience with:
✓ Daily rewards + time trials
✓ Car ownership + garage
✓ Upgrade system
✓ Career progression
✓ Level/XP system
✓ Full economy

Based on actual RR3 game analysis!

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

RR3CommunityServer/Models/ApiModels.cs

@@ -1,5 +1,37 @@
 namespace RR3CommunityServer.Models;
 
+// Progression request/response models
+public class ProgressionUpdate
+{
+    public int? GoldEarned { get; set; }
+    public int? CashEarned { get; set; }
+    public int? ExperienceEarned { get; set; }
+    public int? ReputationEarned { get; set; }
+}
+
+public class CarPurchaseRequest
+{
+    public string SynergyId { get; set; } = string.Empty;
+    public string CarId { get; set; } = string.Empty;
+    public bool UseGold { get; set; } = false;
+}
+
+public class CarUpgradeRequest
+{
+    public string SynergyId { get; set; } = string.Empty;
+    public string CarId { get; set; } = string.Empty;
+    public string UpgradeType { get; set; } = string.Empty; // engine, tires, suspension, etc.
+}
+
+public class CareerEventCompletion
+{
+    public string SynergyId { get; set; } = string.Empty;
+    public string SeriesName { get; set; } = string.Empty;
+    public string EventName { get; set; } = string.Empty;
+    public int StarsEarned { get; set; } // 1-3 stars
+    public double RaceTime { get; set; }
+}
+
 // Standard Synergy API response wrapper
 public class SynergyResponse<T>
 {