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, 0 insertions, 4 deletions

diff --git a/internal/task/task.go b/internal/task/task.go
index eeac49e..7092ce8 100644
--- a/internal/task/task.go
+++ b/internal/task/task.go
@@ -88,11 +88,7 @@ type Task struct {
 	Priority    Priority     `yaml:"priority"   json:"priority"`
 	Tags        []string     `yaml:"tags"       json:"tags"`
 	DependsOn   []string     `yaml:"depends_on" json:"depends_on"`
-	StoryID           string        `yaml:"-"          json:"story_id,omitempty"`
 	BranchName        string        `yaml:"-"          json:"branch_name,omitempty"`
-	AcceptanceCriteria string       `yaml:"-"          json:"acceptance_criteria,omitempty"`
-	CheckerForTaskID   string       `yaml:"-"          json:"checker_for_task_id,omitempty"`
-	CheckerReport      string       `yaml:"-"          json:"checker_report,omitempty"`
 	State             State         `yaml:"-"          json:"state"`
 	RejectionComment  string        `yaml:"-"          json:"rejection_comment,omitempty"`
 	QuestionJSON      string        `yaml:"-"          json:"question,omitempty"`