Configures sparse checkout on new and existing worktrees to exclude
the pipeline state directory. This prevents feature branches from
containing .story_kit/work/ file moves that cause rename/delete merge
conflicts when merging back to master.
Also removes "pick up the story from .story_kit/work/" instruction
from agent prompts since the story content is already in the prompt.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>