refactor: delete unreachable members and redundant package refs

Eight public members had no caller anywhere in src: GitService.GetFileDiffAsync,
SubtaskRepository.DeleteByTaskIdAsync, TaskRepository.GetByListAsync (a
backwards-compat alias for GetByListIdAsync) and .GetByCreatorAsync,
WorktreeRepository.GetByStatesAsync, TaskMonitorViewModel.SetPendingQuestion
(a duplicate of the live-event lambda), PrimeClaudeTabViewModel.ApplyFiredEvent,
and StreamLineFormatter.FormatFile. TaskAttachmentRepository.DeleteAllForTaskAsync
was reachable only from its own test; the ON DELETE CASCADE on task_attachments
already covers it. Tests for the deleted members go with them.

Dropped two package refs the platform already provides: EntityFrameworkCore.Design
in Worker (the design-time factory and the migrations live in Data, which has its
own ref) and System.IO.FileSystem.AccessControl in Installer.Tests (net8.0-windows
ships the ACL APIs in the shared framework).

tests/ClaudeDo.Ui.Tests/Helpers/StreamLineFormatterTests.cs

@@ -91,48 +91,5 @@ public class StreamLineFormatterTests
         Assert.Null(_formatter.FormatLine(delta));
     }
 
-    // --- FormatFile and Trim ---
-
-    [Fact]
-    public void FormatFile_ParsesAllLinesAndReturnsFormattedText()
-    {
-        var lines = new[]
-        {
-            """{"type":"assistant","message":{"content":[{"type":"text","text":"Hello"}]}}""",
-            """{"type":"assistant","message":{"content":[{"type":"tool_use","id":"x","name":"Bash","input":{"command":"ls"}}]}}""",
-            """{"type":"result","result":"Done."}""",
-        };
-        var file = Path.GetTempFileName();
-        try
-        {
-            File.WriteAllLines(file, lines);
-            var result = _formatter.FormatFile(file);
-            Assert.Contains("Hello", result);
-            Assert.Contains("[Bash]", result);
-            Assert.Contains("Done.", result);
-        }
-        finally
-        {
-            File.Delete(file);
-        }
-    }
-
-    [Fact]
-    public void FormatFile_TrimsLargeContent()
-    {
-        var chunk = new string('x', 1000);
-        var line = "{\"type\":\"assistant\",\"message\":{\"content\":[{\"type\":\"text\",\"text\":\"" + chunk + "\"}]}}";
-        var lines = Enumerable.Repeat(line, 65).ToArray();
-        var file = Path.GetTempFileName();
-        try
-        {
-            File.WriteAllLines(file, lines);
-            var result = _formatter.FormatFile(file);
-            Assert.True(result.Length <= 50_200, $"Expected <= 50200 but got {result.Length}");
-        }
-        finally
-        {
-            File.Delete(file);
-        }
-    }
+    // --- Trim ---
 }