Merge branch 'claudedo/5c80a0aba5d9468a96cf809fc7a6e7a1'

src/ClaudeDo.Data/Configuration/TaskEntityConfiguration.cs

@@ -74,6 +74,7 @@ public class TaskEntityConfiguration : IEntityTypeConfiguration<TaskEntity>
         builder.Property(t => t.PlanningPhase).HasColumnName("planning_phase").IsRequired()
             .HasConversion(PhaseConverter).HasDefaultValue(PlanningPhase.None);
         builder.Property(t => t.BlockedByTaskId).HasColumnName("blocked_by_task_id");
+        builder.Property(t => t.DependsOnTaskId).HasColumnName("depends_on_task_id");
         builder.Property(t => t.ScheduledFor).HasColumnName("scheduled_for");
         builder.Property(t => t.Result).HasColumnName("result");
         builder.Property(t => t.ReviewFeedback).HasColumnName("review_feedback");
@@ -119,6 +120,13 @@ public class TaskEntityConfiguration : IEntityTypeConfiguration<TaskEntity>
             .HasForeignKey(t => t.BlockedByTaskId)
             .OnDelete(DeleteBehavior.SetNull);
 
+        // DependsOn: user/MCP-declared predecessor. SetNull on delete so the dependent becomes
+        // pickable rather than blocked forever on a task that no longer exists.
+        builder.HasOne<TaskEntity>()
+            .WithMany()
+            .HasForeignKey(t => t.DependsOnTaskId)
+            .OnDelete(DeleteBehavior.SetNull);
+
         builder.HasOne(t => t.List)
             .WithMany(l => l.Tasks)
             .HasForeignKey(t => t.ListId)
@@ -133,5 +141,6 @@ public class TaskEntityConfiguration : IEntityTypeConfiguration<TaskEntity>
         builder.HasIndex(t => new { t.ListId, t.SortOrder }).HasDatabaseName("idx_tasks_list_sort");
         builder.HasIndex(t => t.ParentTaskId).HasDatabaseName("idx_tasks_parent_task_id");
         builder.HasIndex(t => t.BlockedByTaskId).HasDatabaseName("idx_tasks_blocked_by");
+        builder.HasIndex(t => t.DependsOnTaskId).HasDatabaseName("idx_tasks_depends_on");
     }
 }