test(worker): adapt planning tests to git-backed worktree flow

Update constructor calls (6-arg), seed AppSettings with sibling strategy,
git-init working dirs via GitRepoFixture.InitRepoWithInitialCommit, and
replace McpConfigPath assertions with worktree-path / .mcp.json checks.
Also fixes PlanningHubTests which had the same 3-arg constructor.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/ClaudeDo.Worker.Tests/Planning/WindowsTerminalPlanningLauncherTests.cs

@@ -12,9 +12,11 @@ public sealed class WindowsTerminalPlanningLauncherTests
         return new PlanningSessionStartContext(
             ParentTaskId: "task-1",
             WorkingDir: workingDir,
+            Token: "test-token",
+            WorktreePath: workingDir,
+            BranchName: "claudedo/planning/task1",
             Files: new PlanningSessionFiles(
                 SessionDirectory: dir,
-                McpConfigPath: Path.Combine(dir, "mcp.json"),
                 SystemPromptPath: Path.Combine(dir, "system-prompt.md"),
                 InitialPromptPath: Path.Combine(dir, "initial-prompt.txt")));
     }
@@ -33,7 +35,6 @@ public sealed class WindowsTerminalPlanningLauncherTests
     public async Task LaunchStartAsync_WtMissing_Throws()
     {
         var ctx = MakeStartCtx();
-        File.WriteAllText(ctx.Files.McpConfigPath, "{}");
         File.WriteAllText(ctx.Files.SystemPromptPath, "sp");
         File.WriteAllText(ctx.Files.InitialPromptPath, "ip");