feat(worker): accept #123 task numbers as MCP tool input

TaskIdResolver resolves a #123/bare-123 taskId parameter to its GUID
before any lookup, across every External/ MCP tool that takes a task
id, including the batch tools' id arrays (via delegation to the
already-resolving single-entity methods) and update_task's
dependsOnTaskId (empty string still passes through unchanged as the
clear-link sentinel). An unknown number throws a clear error instead
of a silent null. McpToolDocs.TaskNumberHint tells the agent to refer
to tasks as #<number> when reporting to the user, added to the
description of get_task, list_tasks, add_task, update_task_status and
review_task.

tests/ClaudeDo.Worker.Tests/External/RunHistoryMcpToolsTests.cs

@@ -11,13 +11,15 @@ public sealed class RunHistoryMcpToolsTests : IDisposable
     private readonly DbFixture _db = new();
     private readonly ClaudeDoDbContext _ctx;
     private readonly TaskRunRepository _runs;
+    private readonly TaskRepository _tasks;
     private readonly RunHistoryMcpTools _sut;
 
     public RunHistoryMcpToolsTests()
     {
         _ctx = _db.CreateContext();
         _runs = new TaskRunRepository(_ctx);
-        _sut = new RunHistoryMcpTools(_runs);
+        _tasks = new TaskRepository(_ctx);
+        _sut = new RunHistoryMcpTools(_runs, _tasks);
     }
 
     public void Dispose() { _ctx.Dispose(); _db.Dispose(); }