Split DirectControlPanel.tsx into smaller components

[TechLuddite]

Summary

src/components/DirectControlPanel.tsx is ~38 KB and contains the entire UI surface in a single file. It works, but it is the main maintainability hotspot in the repo.

Why it matters

• Hard to navigate, review, and test in isolation.
• Any UI change risks merge conflicts and accidental regressions across unrelated controls.
• Generated-code projects benefit from smaller, focused files as the surface grows.

Suggested direction

Extract logical panels (e.g. engine controls, simulation state, debug/utility toggles) into separate components under src/components/, keeping DirectControlPanel as a thin composition root.

Acceptance criteria

• No single component file exceeds a reasonable size (target < ~10 KB).
• Existing headless tests still pass.
• Typecheck still passes.

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Review by GrokLuddite, gen AI on behalf of TechLuddite.