feat(worker): surface startup recovery via OperationProgress channel

The six Lifecycle/*Recovery hosted services now broadcast one
OperationProgress("startup-recovery", <phase>, current, total) message each
after they finish, instead of leaving the UI on a bare "connecting" text
during worker startup. IslandsShellViewModel subscribes and swaps in
"Recovering... (i/n)" (existing ops.worker.startupRecovery key, no locale
changes) while Worker.IsReconnecting is true, and clears it once actually
connected so a later transient reconnect doesn't replay stale text.

OperationProgress broadcasts to Clients.All with no replay-on-connect, so a
UI that hasn't finished its SignalR handshake yet can miss some or all of
these messages and simply keep showing "connecting" as before -- accepted
rather than adding a cached-state + reconnect-replay path (mirroring
RefreshExternalMergeConflictsAsync) for what is a fast, best-effort,
local-only startup sweep with no UI-visible failure mode beyond that.

tests/ClaudeDo.Worker.Tests/Lifecycle/AttachmentOrphanRecoveryTests.cs

@@ -1,5 +1,6 @@
 using ClaudeDo.Data;
 using ClaudeDo.Data.Models;
+using ClaudeDo.Worker.Hub;
 using ClaudeDo.Worker.Lifecycle;
 using ClaudeDo.Worker.Tests.Infrastructure;
 using Microsoft.Extensions.Logging.Abstractions;
@@ -49,14 +50,18 @@ public sealed class AttachmentOrphanRecoveryTests : IDisposable
         Directory.CreateDirectory(liveDir);
         Directory.CreateDirectory(orphanDir);
 
+        var hubContext = new CapturingHubContext();
         var sut = new AttachmentOrphanRecovery(
             _db.CreateFactory(), store,
+            new HubBroadcaster(hubContext),
             NullLogger<AttachmentOrphanRecovery>.Instance);
 
         await sut.StartAsync(CancellationToken.None);
 
         Assert.True(Directory.Exists(liveDir), "Live task dir should be kept");
         Assert.False(Directory.Exists(orphanDir), "Orphan dir should be deleted");
+        Assert.Contains(hubContext.Proxy.Calls, c =>
+            c.Method == "OperationProgress" && (string)c.Args[0]! == "startup-recovery");
     }
 
     [Fact]
@@ -66,10 +71,15 @@ public sealed class AttachmentOrphanRecoveryTests : IDisposable
         var missingRoot = Path.Combine(Path.GetTempPath(), $"claudedo_missing_{Guid.NewGuid():N}");
         var store = new AttachmentStore(missingRoot);
 
+        var hubContext = new CapturingHubContext();
         var sut = new AttachmentOrphanRecovery(
             _db.CreateFactory(), store,
+            new HubBroadcaster(hubContext),
             NullLogger<AttachmentOrphanRecovery>.Instance);
 
         await sut.StartAsync(CancellationToken.None); // must not throw
+
+        Assert.Contains(hubContext.Proxy.Calls, c =>
+            c.Method == "OperationProgress" && (string)c.Args[0]! == "startup-recovery");
     }
 }