Story 26: Establish TDD workflow and quality gates

Add workflow engine with acceptance gates, test recording, and review
queue. Frontend displays gate status (blocked/ready), test summaries,
failing badges, and warnings. Proceed action is disabled when gates
are not met. Includes 13 unit tests (Vitest) and 9 E2E tests
(Playwright) covering all five acceptance criteria.

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

.story_kit/stories/current/26_establish_tdd_workflow_and_gates.md

@@ -1,15 +0,0 @@
-# Story 26: Establish the TDD Workflow and Gates
-
-## User Story
-As a user, I want a clear, enforceable TDD workflow with quality gates, so development is test-first and regressions are blocked.
-
-## Acceptance Criteria
-- [ ] A test-first workflow is defined and enforced before implementation begins.
-- [ ] Each story requires both unit tests and integration tests (standard Rust `tests/` layout).
-- [ ] A test plan is produced and approved before any code changes.
-- [ ] Stories cannot be accepted unless all required tests pass.
-- [ ] Only one failing test is allowed at a time during red-green-refactor.
-
-## Out of Scope
-- Backfilling tests for legacy code (covered by a separate story).
-- Adding new test frameworks beyond those defined in `specs/tech/STACK.md`.