feat: Add Stripe payment integration and subscription management

- Add Stripe.net SDK for payment processing
- Implement StripeService with checkout sessions, customer portal, webhooks
- Implement SubscriptionService for quota management
- Add quota enforcement to CVCheckService
- Create Pricing, Billing, Settings pages
- Add checkout success/cancel pages
- Update Check and Dashboard with usage indicators
- Add ResetMonthlyUsageJob for billing cycle resets
- Add database migration for subscription fields

Plan tiers: Free (3 checks), Professional £49/mo (30), Enterprise £199/mo (unlimited)

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

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

src/TrueCV.Application/DTOs/SubscriptionInfoDto.cs

@@ -0,0 +1,16 @@
+using TrueCV.Domain.Enums;
+
+namespace TrueCV.Application.DTOs;
+
+public class SubscriptionInfoDto
+{
+    public UserPlan Plan { get; set; }
+    public int ChecksUsedThisMonth { get; set; }
+    public int MonthlyLimit { get; set; }
+    public int ChecksRemaining { get; set; }
+    public bool IsUnlimited { get; set; }
+    public string? SubscriptionStatus { get; set; }
+    public DateTime? CurrentPeriodEnd { get; set; }
+    public bool HasActiveSubscription { get; set; }
+    public string DisplayPrice { get; set; } = string.Empty;
+}