feat: Add SitePageSettings - simplified page management system

- New entities: SitePageSettings + SitePageImage (4 fixed pages)
- EF Migration: AddSitePageSettings (SitePageSettings + SitePageImages tables)
- Proto: sitepagesettings.proto with 5 RPCs
- CQRS: GetPageSettings, GetAllPageSettings, SavePageSettings, SavePageImage, DeletePageImage
- gRPC Service: SitePageSettingsService (auto-registered)
- Proto NuGet bumped to 0.0.180

src/CMSMicroservice.Infrastructure/Persistence/Configurations/SitePageSettingsConfiguration.cs

@@ -0,0 +1,44 @@
+using CMSMicroservice.Domain.Entities.Content;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+
+namespace CMSMicroservice.Infrastructure.Persistence.Configurations;
+
+public class SitePageSettingsConfiguration : IEntityTypeConfiguration<SitePageSettings>
+{
+    public void Configure(EntityTypeBuilder<SitePageSettings> builder)
+    {
+        builder.ToTable("SitePageSettings");
+        builder.HasKey(x => x.Id);
+
+        builder.Property(x => x.PageKey)
+            .IsRequired()
+            .HasMaxLength(50);
+
+        builder.Property(x => x.Title)
+            .IsRequired()
+            .HasMaxLength(200);
+
+        builder.Property(x => x.MetaDescription)
+            .HasMaxLength(300);
+
+        builder.Property(x => x.HeroTitle)
+            .HasMaxLength(200);
+
+        builder.Property(x => x.HeroSubtitle)
+            .HasMaxLength(500);
+
+        builder.Property(x => x.IsActive)
+            .IsRequired()
+            .HasDefaultValue(true);
+
+        // SettingsJson — ستون JSON بدون محدودیت طول
+        builder.Property(x => x.SettingsJson)
+            .HasColumnType("nvarchar(max)");
+
+        // ایندکس یکتا روی PageKey
+        builder.HasIndex(x => x.PageKey)
+            .IsUnique()
+            .HasDatabaseName("IX_SitePageSettings_PageKey");
+    }
+}