feat(tickets): sweep all project boards for assigned tickets and tasks

tests/ClaudeDo.Worker.Tests/Tickets/TicketImportServiceTests.cs

@@ -106,6 +106,20 @@ public sealed class TicketImportServiceTests : IDisposable
         Assert.Equal(1, await ctx.Tasks.CountAsync(t => t.TicketRef == "bandel:1"));
     }
 
+    [Fact]
+    public async Task Ticket_already_imported_into_another_list_is_not_imported_again()
+    {
+        var (import, ctx) = await HarnessAsync();
+        ctx.Lists.Add(new ListEntity { Id = "l2", Name = "Other", CreatedAt = DateTime.UtcNow, DefaultCommitType = "chore" });
+        await ctx.SaveChangesAsync();
+        await SeedExistingTaskAsync(ctx, "l2", "bandel:1");
+
+        var result = await import.ImportAsync(ListId, CancellationToken.None);
+
+        Assert.Equal(1, result.Created); // only #3
+        Assert.Equal(1, await ctx.Tasks.CountAsync(t => t.TicketRef == "bandel:1"));
+    }
+
     [Fact]
     public async Task Throws_when_the_list_has_no_ticket_project()
     {