Add SQLite content storage with queue-based operations

AGENTS.md

@@ -8,6 +8,7 @@ Ignore the "archived" directory.
 - `build.sh` is passing without errors or warnings
 - Test coverage is greater than 80% and `coverage.sh` is not failing
 - Problems are not hidden, problems are addressed.
+- Report breaking changes and ask how to handle them, do not assume migrations are required.
 
 # C# Code Style
 

clean.sh

@@ -12,3 +12,5 @@ rm -rf src/Core/obj
 
 rm -rf src/Main/bin
 rm -rf src/Main/obj
+
+rm -rf tests/Core.Tests/TestResults

src/Core/Core.csproj

@@ -6,4 +6,9 @@
         <TargetFramework>net10.0</TargetFramework>
     </PropertyGroup>
 
+    <ItemGroup>
+      <PackageReference Include="cuid.net" />
+      <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" />
+    </ItemGroup>
+
 </Project>

src/Core/Storage/ContentStorageDbContext.cs

@@ -0,0 +1,178 @@
+using System.Globalization;
+using KernelMemory.Core.Storage.Entities;
+using Microsoft.EntityFrameworkCore;
+
+namespace KernelMemory.Core.Storage;
+
+/// <summary>
+/// Database context for content storage.
+/// Manages Content and Operations tables with proper SQLite configuration.
+/// </summary>
+public class ContentStorageDbContext : DbContext
+{
+    public DbSet<ContentRecord> Content { get; set; } = null!;
+    public DbSet<OperationRecord> Operations { get; set; } = null!;
+
+    public ContentStorageDbContext(DbContextOptions<ContentStorageDbContext> options) : base(options)
+    {
+    }
+
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {
+        base.OnModelCreating(modelBuilder);
+
+        // Configure Content table
+        modelBuilder.Entity<ContentRecord>(entity =>
+        {
+            // Hardcoded table name as per specification
+            entity.ToTable("km_content");
+
+            // Primary key
+            entity.HasKey(e => e.Id);
+
+            // Required fields
+            entity.Property(e => e.Id)
+                .IsRequired()
+                .HasMaxLength(32); // Cuid2 is typically 25-32 characters
+
+            entity.Property(e => e.Content)
+                .IsRequired();
+
+            entity.Property(e => e.MimeType)
+                .IsRequired()
+                .HasMaxLength(255);
+
+            entity.Property(e => e.ByteSize)
+                .IsRequired();
+
+            entity.Property(e => e.Ready)
+                .IsRequired();
+
+            // DateTimeOffset stored as ISO 8601 string in SQLite
+            entity.Property(e => e.ContentCreatedAt)
+                .IsRequired()
+                .HasConversion(
+                    v => v.ToString("O"),
+                    v => DateTimeOffset.Parse(v, CultureInfo.InvariantCulture));
+
+            entity.Property(e => e.RecordCreatedAt)
+                .IsRequired()
+                .HasConversion(
+                    v => v.ToString("O"),
+                    v => DateTimeOffset.Parse(v, CultureInfo.InvariantCulture));
+
+            entity.Property(e => e.RecordUpdatedAt)
+                .IsRequired()
+                .HasConversion(
+                    v => v.ToString("O"),
+                    v => DateTimeOffset.Parse(v, CultureInfo.InvariantCulture));
+
+            // Optional fields
+            entity.Property(e => e.Title)
+                .IsRequired()
+                .HasDefaultValue(string.Empty);
+
+            entity.Property(e => e.Description)
+                .IsRequired()
+                .HasDefaultValue(string.Empty);
+
+            // JSON fields - store as TEXT in SQLite
+            entity.Property(e => e.TagsJson)
+                .IsRequired()
+                .HasColumnType("TEXT")
+                .HasDefaultValue("[]");
+
+            entity.Property(e => e.MetadataJson)
+                .IsRequired()
+                .HasColumnType("TEXT")
+                .HasDefaultValue("{}");
+
+            // Ignore computed properties (not stored in database)
+            entity.Ignore(e => e.Tags);
+            entity.Ignore(e => e.Metadata);
+
+            // Indexes
+            entity.HasIndex(e => e.Ready)
+                .HasDatabaseName("IX_km_content_Ready");
+        });
+
+        // Configure Operations table
+        modelBuilder.Entity<OperationRecord>(entity =>
+        {
+            // Hardcoded table name as per specification
+            entity.ToTable("km_operations");
+
+            // Primary key
+            entity.HasKey(e => e.Id);
+
+            // Required fields
+            entity.Property(e => e.Id)
+                .IsRequired()
+                .HasMaxLength(32);
+
+            entity.Property(e => e.Complete)
+                .IsRequired();
+
+            entity.Property(e => e.Cancelled)
+                .IsRequired();
+
+            entity.Property(e => e.ContentId)
+                .IsRequired()
+                .HasMaxLength(32);
+
+            // DateTimeOffset stored as ISO 8601 string in SQLite
+            entity.Property(e => e.Timestamp)
+                .IsRequired()
+                .HasConversion(
+                    v => v.ToString("O"),
+                    v => DateTimeOffset.Parse(v, CultureInfo.InvariantCulture));
+
+            entity.Property(e => e.LastFailureReason)
+                .IsRequired()
+                .HasDefaultValue(string.Empty);
+
+            // Nullable DateTimeOffset for locking
+            entity.Property(e => e.LastAttemptTimestamp)
+                .HasConversion(
+                    v => v.HasValue ? v.Value.ToString("O") : null,
+                    v => v == null ? (DateTimeOffset?)null : DateTimeOffset.Parse(v, CultureInfo.InvariantCulture));
+
+            // JSON fields - store as TEXT in SQLite
+            entity.Property(e => e.PlannedStepsJson)
+                .IsRequired()
+                .HasColumnType("TEXT")
+                .HasDefaultValue("[]");
+
+            entity.Property(e => e.CompletedStepsJson)
+                .IsRequired()
+                .HasColumnType("TEXT")
+                .HasDefaultValue("[]");
+
+            entity.Property(e => e.RemainingStepsJson)
+                .IsRequired()
+                .HasColumnType("TEXT")
+                .HasDefaultValue("[]");
+
+            entity.Property(e => e.PayloadJson)
+                .IsRequired()
+                .HasColumnType("TEXT")
+                .HasDefaultValue("{}");
+
+            // Ignore computed properties (not stored in database)
+            entity.Ignore(e => e.PlannedSteps);
+            entity.Ignore(e => e.CompletedSteps);
+            entity.Ignore(e => e.RemainingSteps);
+            entity.Ignore(e => e.Payload);
+
+            // Indexes as per specification
+            entity.HasIndex(e => new { e.ContentId, e.Timestamp })
+                .HasDatabaseName("IX_km_operations_ContentId_Timestamp");
+
+            entity.HasIndex(e => new { e.Complete, e.Timestamp })
+                .HasDatabaseName("IX_km_operations_Complete_Timestamp");
+
+            entity.HasIndex(e => e.Timestamp)
+                .HasDatabaseName("IX_km_operations_Timestamp");
+        });
+    }
+}