Add Daily Rewards & Time Trials features

NEW FEATURES:
- Daily login rewards with Gold and Cash
- Daily time trial racing events
- FREE gold purchase system
- Streak tracking for consecutive days
- Web panel for managing rewards and events

ENDPOINTS ADDED:
- GET/POST /synergy/rewards/daily/{id} - Daily rewards
- POST /synergy/rewards/gold/purchase - Buy gold (FREE)
- GET /synergy/rewards/timetrials - Active events
- POST /synergy/rewards/timetrials/{id}/submit - Submit times

DATABASE:
- DailyReward table - tracks claims and streaks
- TimeTrial table - racing events with rewards
- TimeTrialResult table - player submissions
- User.Gold and User.Cash - currency tracking

WEB PANEL:
- /admin/rewards - Manage all reward features
- Create/edit/activate time trial events
- View reward statistics and history
- Gold packages in catalog (100, 500, 1000, 5000)

FOCUS:
- Single-player progression features
- NO race teams or multiplayer
- Perfect for offline play
- All purchases are FREE in community server

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

RR3CommunityServer/Pages/Rewards.cshtml.cs

@@ -0,0 +1,102 @@
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.RazorPages;
+using Microsoft.EntityFrameworkCore;
+using RR3CommunityServer.Data;
+using static RR3CommunityServer.Data.RR3DbContext;
+
+namespace RR3CommunityServer.Pages;
+
+public class RewardsModel : PageModel
+{
+    private readonly RR3DbContext _context;
+
+    public RewardsModel(RR3DbContext context)
+    {
+        _context = context;
+    }
+
+    public int TodaysClaims { get; set; }
+    public int ActiveTimeTrials { get; set; }
+    public int TotalGoldDistributed { get; set; }
+    public int TrialCompletions { get; set; }
+    public List<TimeTrial> TimeTrials { get; set; } = new();
+    public List<DailyReward> RecentRewards { get; set; } = new();
+
+    public async Task OnGetAsync()
+    {
+        var today = DateTime.UtcNow.Date;
+
+        TodaysClaims = await _context.DailyRewards
+            .Where(r => r.RewardDate.Date == today && r.Claimed)
+            .CountAsync();
+
+        ActiveTimeTrials = await _context.TimeTrials
+            .Where(t => t.Active)
+            .CountAsync();
+
+        TotalGoldDistributed = await _context.DailyRewards
+            .Where(r => r.Claimed)
+            .SumAsync(r => r.GoldAmount);
+
+        TrialCompletions = await _context.TimeTrialResults.CountAsync();
+
+        TimeTrials = await _context.TimeTrials
+            .OrderByDescending(t => t.Active)
+            .ThenByDescending(t => t.StartDate)
+            .ToListAsync();
+
+        RecentRewards = await _context.DailyRewards
+            .Where(r => r.Claimed)
+            .OrderByDescending(r => r.ClaimedAt)
+            .Take(20)
+            .ToListAsync();
+    }
+
+    public async Task<IActionResult> OnPostAddTrialAsync(
+        string name, string trackName, string carName,
+        DateTime startDate, DateTime endDate,
+        double targetTime, int goldReward, int cashReward)
+    {
+        var trial = new TimeTrial
+        {
+            Name = name,
+            TrackName = trackName,
+            CarName = carName,
+            StartDate = startDate,
+            EndDate = endDate,
+            TargetTime = targetTime,
+            GoldReward = goldReward,
+            CashReward = cashReward,
+            Active = true
+        };
+
+        _context.TimeTrials.Add(trial);
+        await _context.SaveChangesAsync();
+
+        return RedirectToPage();
+    }
+
+    public async Task<IActionResult> OnPostToggleTrialAsync(int trialId)
+    {
+        var trial = await _context.TimeTrials.FindAsync(trialId);
+        if (trial != null)
+        {
+            trial.Active = !trial.Active;
+            await _context.SaveChangesAsync();
+        }
+
+        return RedirectToPage();
+    }
+
+    public async Task<IActionResult> OnPostDeleteTrialAsync(int trialId)
+    {
+        var trial = await _context.TimeTrials.FindAsync(trialId);
+        if (trial != null)
+        {
+            _context.TimeTrials.Remove(trial);
+            await _context.SaveChangesAsync();
+        }
+
+        return RedirectToPage();
+    }
+}