fix(worker): advance planning chains and parents on stale-Running recovery

RecoverStaleRunningAsync bulk-flipped Running rows to Failed via raw
ExecuteUpdate, skipping the chain/parent side effects every other terminal
transition triggers. After a worker crash mid-run of a planning/improvement
child, the chain successor's BlockedByTaskId was never cleared and a
WaitingForChildren parent could wedge forever with no event left to
re-check it. Now each recovered task runs the same OnChildTerminalAsync
side effects (chain advance + parent advance) as FailAsync, best-effort.

tests/ClaudeDo.Worker.Tests/State/TaskStateServiceTests.cs

@@ -456,6 +456,25 @@ public sealed class TaskStateServiceTests : IDisposable
         Assert.StartsWith("[stale] ", t.Result);
     }
 
+    [Fact]
+    public async Task RecoverStaleRunningAsync_ResolvesBlockedSuccessor_AndAdvancesParent()
+    {
+        var parent = await SeedTaskAsync(TaskStatus.WaitingForChildren, phase: PlanningPhase.Finalized);
+        var c0 = await SeedTaskAsync(TaskStatus.Running, parentId: parent, sortOrder: 0);
+        var c1 = await SeedTaskAsync(TaskStatus.Queued, parentId: parent, sortOrder: 1, blockedBy: c0);
+
+        var count = await _sut.RecoverStaleRunningAsync("worker restart", default);
+
+        Assert.Equal(1, count);
+        Assert.Equal(TaskStatus.Failed, await GetStatusAsync(c0));
+        // c1 was blocked on the crashed task; the chain coordinator resolves it (cancels it,
+        // since the predecessor didn't finish successfully) instead of leaving it Queued with
+        // a dangling BlockedByTaskId that the picker would skip forever.
+        Assert.Equal(TaskStatus.Cancelled, await GetStatusAsync(c1));
+        // Both children are now terminal, so the WaitingForChildren parent advances.
+        Assert.Equal(TaskStatus.WaitingForReview, await GetStatusAsync(parent));
+    }
+
     // ─── Child terminal → chain advance ───────────────────────────────────
 
     [Fact]