Initial commit: Predictalytics solution

Clean Architecture .NET 8 solution (Domain/Application/Infrastructure/Api/Worker/WinFormsHost)
for analyzing Polymarket traders for copytrading/strategy-replication candidates.

Includes EF Core InitialBaseline migration and DB secrets removed from source/config
in preparation for version control.

src/Predictalytics.Domain/Interfaces/ITraderRepository.cs

@@ -0,0 +1,26 @@
+using Predictalytics.Domain.Entities;
+using Predictalytics.Domain.Enums;
+
+namespace Predictalytics.Domain.Interfaces;
+
+public interface ITraderRepository
+{
+    Task<Trader?> GetByIdAsync(int id, CancellationToken ct = default);
+    Task<Trader?> GetByPlatformIdAsync(PlatformType platform, string platformUserId, CancellationToken ct = default);
+    Task<IReadOnlyList<Trader>> GetAllAsync(PlatformType? platform = null, int skip = 0, int take = 50, CancellationToken ct = default);
+    Task<IReadOnlyList<Trader>> GetWatchlistedAsync(CancellationToken ct = default);
+    Task<IReadOnlyList<Trader>> GetTopByScoreAsync(int count = 20, CancellationToken ct = default);
+    Task<IReadOnlyList<Trader>> GetTopByPnLAsync(int count = 5, DateTime? since = null, CancellationToken ct = default);
+    Task<int> GetCountAsync(PlatformType? platform = null, CancellationToken ct = default);
+    Task AddAsync(Trader trader, CancellationToken ct = default);
+    Task UpdateAsync(Trader trader, CancellationToken ct = default);
+    Task DeleteAsync(int id, CancellationToken ct = default);
+
+    /// <summary>Get traders that need trade history update (LastTradesUpdatedAt is null or older than given hours).</summary>
+    Task<IReadOnlyList<Trader>> GetTradersDueForTradeUpdateAsync(int cooldownHours = 6, int take = 20, CancellationToken ct = default);
+
+    /// <summary>Get traders that haven't been polled in a long time or have a prolonged API error for cleanup.</summary>
+    Task<IReadOnlyList<Trader>> GetTradersForCleanupAsync(DateTime inactiveSince, DateTime errorSince, int take = 50, CancellationToken ct = default);
+
+    Task<IReadOnlyList<Trader>> SearchAsync(string query, int take = 20, CancellationToken ct = default);
+}