fix(ui): make diff-stat parsing locale-safe and dedupe the two parsers

TaskRowViewModel had its own ParseDiffStat expecting "+12"/"-3" tokens that
`git diff --stat` never emits, so the row badge always showed 0/0. Meanwhile
DetailsIslandViewModel's parser matched only the English words
"insertion"/"deletion", so it broke on a localized git (e.g. German Windows:
"Einfügung(en)"/"Löschung(en)").

Row and detail badge now share one parser, anchored on git's untranslated
(+)/(-) suffix instead of the language-dependent word before it, so it reads
correctly in any locale. Also corrected the Worker CLAUDE.md's branch-name
claim (`claudedo/{taskId[:8]}`) to match the actual full-GUID branch name.

tests/ClaudeDo.Worker.Tests/UiVm/ParseDiffStatTests.cs

@@ -1,4 +1,6 @@
+using ClaudeDo.Data.Models;
 using ClaudeDo.Ui.ViewModels.Islands;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
 
 namespace ClaudeDo.Worker.Tests.UiVm;
 
@@ -35,4 +37,59 @@ public class ParseDiffStatTests
         Assert.Equal(5, add);
         Assert.Equal(0, del);
     }
+
+    [Fact]
+    public void Deletions_Only_Returns_Zero_Insertions()
+    {
+        var (add, del) = DetailsIslandViewModel.ParseDiffStat("1 file changed, 4 deletions(-)");
+        Assert.Equal(0, add);
+        Assert.Equal(4, del);
+    }
+
+    // German-Windows git localizes "insertion(s)"/"deletion(s)" (e.g. "Einfügung(en)"/
+    // "Löschung(en)") but keeps the (+)/(-) suffix untranslated — the regex anchors on that.
+    [Fact]
+    public void German_Locale_Stat_Parses_Both()
+    {
+        var (add, del) = DetailsIslandViewModel.ParseDiffStat("2 Dateien geändert, 10 Einfügungen(+), 3 Löschungen(-)");
+        Assert.Equal(10, add);
+        Assert.Equal(3, del);
+    }
+
+    [Fact]
+    public void German_Locale_Insertions_Only_Returns_Zero_Deletions()
+    {
+        var (add, del) = DetailsIslandViewModel.ParseDiffStat("1 Datei geändert, 5 Einfügung(en)(+)");
+        Assert.Equal(5, add);
+        Assert.Equal(0, del);
+    }
+
+    // TaskRowViewModel used to run its own broken parser (expecting "+12"/"-3" tokens that
+    // `git diff --stat` never emits) — pin it to the same shared, correct parser as the detail badge.
+    [Fact]
+    public void TaskRowViewModel_UpdateFromEntity_Parses_Real_DiffStat_Format()
+    {
+        var task = new TaskEntity
+        {
+            Id = "t1",
+            ListId = "l1",
+            Title = "task",
+            CreatedAt = DateTime.UtcNow,
+            Status = TaskStatus.Done,
+            Worktree = new WorktreeEntity
+            {
+                TaskId = "t1",
+                Path = "/tmp/wt",
+                BranchName = "claudedo/t1",
+                BaseCommit = "abc",
+                DiffStat = "2 files changed, 10 insertions(+), 3 deletions(-)",
+                CreatedAt = DateTime.UtcNow,
+            },
+        };
+
+        var row = TaskRowViewModel.FromEntity(task);
+
+        Assert.Equal(10, row.DiffAdditions);
+        Assert.Equal(3, row.DiffDeletions);
+    }
 }