chore: remove stories/checker backend dead code

Remove the dead stories/checker backend tracked as design debt in CLAUDE.md:
- Delete internal/api/stories.go, stories_test.go, elaborate.go
- Delete internal/task/story.go, story_test.go
- Remove story/checker columns from storage schema and all CRUD methods
- Remove checkStoryCompletion, spawnCheckerTask, triggerStoryDeploy,
  createValidationTask, checkValidationResult, ShipStory, CheckStoryCompletion
  from executor; simplify handleRunResult
- Remove story/checker fields from task.Task (StoryID, AcceptanceCriteria,
  CheckerForTaskID, CheckerReport)
- Remove story routes and geminiBinPath from API server
- Move claudeJSONResult/extractJSON from elaborate.go to validate.go
- Rename ensureStoryBranch -> ensureBranch in ContainerRunner
- Fix git identity in bare-repo tests; fix initial-branch to use main

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 13 insertions, 3 deletions

diff --git a/internal/api/webhook_test.go b/internal/api/webhook_test.go
index 05fe82c..f0ede7c 100644
--- a/internal/api/webhook_test.go
+++ b/internal/api/webhook_test.go
@@ -422,11 +422,21 @@ func TestGitHubWebhook_PushEvent_SyncsLocalBareRepo(t *testing.T) {
 	// Create a "github" source bare repo with a commit.
 	githubBare := filepath.Join(dir, "github.git")
 	localBare := filepath.Join(dir, "local.git")
-	for _, bare := range []string{githubBare, localBare} {
-		if out, err := exec.Command("git", "init", "--bare", bare).CombinedOutput(); err != nil {
-			t.Fatalf("git init bare %s: %v\n%s", bare, err, out)
+	initBare := func(path string) {
+		t.Helper()
+		out, err := exec.Command("git", "init", "--bare", "--initial-branch=main", path).CombinedOutput()
+		if err != nil {
+			// Fallback for older git: init then update HEAD to main.
+			if out2, err2 := exec.Command("git", "init", "--bare", path).CombinedOutput(); err2 != nil {
+				t.Fatalf("git init bare %s: %v\n%s", path, err2, out2)
+			}
+			if out2, err2 := exec.Command("git", "-C", path, "symbolic-ref", "HEAD", "refs/heads/main").CombinedOutput(); err2 != nil {
+				t.Fatalf("set HEAD to main %s: %v\n%s\n%s", path, err, out, out2)
+			}
 		}
 	}
+	initBare(githubBare)
+	initBare(localBare)
 	// Seed githubBare with a commit via a temp clone.
 	clone := filepath.Join(dir, "clone")
 	run := func(args ...string) {