fix(editor): restore scene auto-framing on load

[ActArtech]

What does this PR do?

Fixes the empty-viewport camera bug (full root-cause chain documented in wiki/empty-viewport-postmortem.md, filed by the base PR):

• Restores useAutoFrame() (import + call) in packages/editor/src/components/editor/index.tsx — it was deleted in e688792, so nothing emitted camera-controls:fit-scene and the camera stayed at the hardcoded (20, 20, 20) default pose on every scene load.
• Stops the level-follow effect in CustomCameraControls from clobbering the auto-framed pose: the first-load default pose now only applies to a scene-less editor, and moveTo only fires on real level switches (not the initial null → level transition).
• Re-emits camera-controls:fit-scene once the viewer reports scene-ready, so late load-driven effects can't leave the camera unframed on fast (client-side navigation) loads.
• Removes a process.env.NODE_ENV gate around the window.__pascalCameraControls debug handle that threw in Turbopack-served workspace sources, leaving the handle permanently unset.

How to test

1. bun run dev in apps/editor, open /scenes, click into a large scene (e.g. Hagia Sophia ground floor) via the scene list.
2. Expected: the camera frames the building mass in the 3D viewport (previously: interior-of-footprint / empty view).
3. Switch levels and back — the camera holds its pose except on real level switches.
4. Hard-refresh on a direct scene URL — framing is still correct.

Screenshots / screen recording

Before/after evidence captured during the fix is documented in wiki/empty-viewport-postmortem.md (base PR). Recording can be attached on request.

Checklist

• I've tested this locally with bun dev
• My code follows the existing code style (run bun check to verify) — biome check output on the touched files is identical at HEAD (pre-existing CRLF noise)
• I've updated relevant documentation (if applicable) — covered by the base PR's postmortem
• This PR targets docs/hs-standard (stacked on the documentation PR, not main)