The `drafted` story state is no longer used since create-story now sets
status directly to `ready-for-dev`. This PR removes all references to
this legacy state from BMM documentation and workflow files.
Changes:
- Remove `drafted` from story status definitions and state machine docs
- Remove dead story-context file detection (story-context files no longer exist)
- Replace "draft" verb with "create" in story-related messaging
- Add legacy `drafted` → `ready-for-dev` migration in sprint-status
- Clarify that validate-create-story is optional and doesn't change status
- Document story handoff sequence: create-story → (optional) validate → dev-story
Story lifecycle is now: backlog → ready-for-dev → in-progress → review → done
Closes#1089🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>