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.

src/ClaudeDo.Ui/ViewModels/Islands/TaskRowViewModel.cs

@@ -500,7 +500,7 @@ public sealed partial class TaskRowViewModel : ViewModelBase
         // Any entity-backed refresh reflects a settled state, so the transient creation-phase
         // banner (set from the OperationProgress broadcast) has nothing left to announce.
         CreationPhase     = null;
-        var (add, del) = ParseDiffStat(t.Worktree?.DiffStat);
+        var (add, del) = DetailsIslandViewModel.ParseDiffStat(t.Worktree?.DiffStat);
         Number            = t.Number;
         Title             = t.Title;
         ListName          = t.List?.Name ?? "";
@@ -529,18 +529,4 @@ public sealed partial class TaskRowViewModel : ViewModelBase
         FailureTurnsUsed  = t.FailureTurnsUsed;
         FailureMaxTurns   = t.FailureMaxTurns;
     }
-
-    // Best-effort parse of diff stat strings like "+12 -3" or "12 additions, 3 deletions".
-    private static (int add, int del) ParseDiffStat(string? s)
-    {
-        if (string.IsNullOrWhiteSpace(s)) return (0, 0);
-        int add = 0, del = 0;
-        var parts = s.Split(new[] { ' ', ',', '\t' }, StringSplitOptions.RemoveEmptyEntries);
-        foreach (var p in parts)
-        {
-            if (p.Length > 1 && p[0] == '+' && int.TryParse(p.AsSpan(1), out var a)) add = a;
-            else if (p.Length > 1 && (p[0] == '-' || p[0] == '\u2212') && int.TryParse(p.AsSpan(1), out var d)) del = d;
-        }
-        return (add, del);
-    }
 }