Close the gap where docs/use-cases/*.feature claimed to be the behavior spec but nothing executed them — so scenarios drifted (the stale "auto summarizes every new video" and "manual is the default" were proof). Decision (per issue #5 BDD-runner fork): no godog — keep .feature as design records, add a cheap name-coverage gate instead. TestScenarioCoverage parses every scenario and asserts each non-@pending one maps to an existing Go test in the scenarioCoverage manifest; it flags unmapped scenarios, missing/renamed tests, and stale entries. It checks the link, not that the test exercises the scenario (the deliberate trade for skipping godog). Also: - Fix the stale ADR-018 drift: "Manual is the default" -> auto is the default for new users; added an explicit default scenario + a plain manual scenario. - Tag 4 documented-but-unbuilt/untested scenarios @pending with reasons (Vimeo connect, BYO config flow, logout->welcome, re-register-after-delete) so they are tracked without a false coverage claim. - CLAUDE.md BDD section now describes the real setup (design records + the gate + @pending convention) instead of claiming an executable spec. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>