Left over from the fundamentals work. Verified orphaned before removing: not in vite.config.ts (default build input is index.html alone, and dist/ only ever contained index.html, so it never shipped), not referenced by any script, config or module, and imported by nothing. Its only mention anywhere was its own header comment — the many other "harness" hits in the repo are the factor / backtest IC harness, which is unrelated and stays. Removes frontend/src/dev entirely. The pattern it embodied — a fixture-seeded page for eyeballing one component without a backend — is still the only way to see a component render, since the frontend has no test runner. But that is worth recreating per component on the spot, not preserving as a stale file pinned to one panel. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>