fix(mcp): register ticket import tools in the external MCP container

The external MCP server has its own DI container; TicketMcpTools could not
resolve TicketImportService there, so both tools failed at runtime. Also
surface a skipped import in the prime outcome and treat a sweep where every
project board fails as an error instead of an empty backlog.

tests/ClaudeDo.Worker.Tests/Prime/PrimeRunnerTests.cs

@@ -311,6 +311,7 @@ public class PrimeRunnerTests : IDisposable
         var outcome = await runner.FireAsync(Schedule(PrimeActionKind.ImportTickets), CancellationToken.None);
 
         Assert.True(outcome.Success);
+        Assert.Contains("not configured", outcome.Message);
         var only = Assert.Single(claude.AllArguments);
         Assert.Contains(DailyPrepPrompt.SetMyDayTool, only);
     }