Fix preview coordinate updates during camera movement

[Da7-Tech]

Summary

• Recalculate the block preview position when the camera moves, not only when the mouse moves or placement is active.
• Keeps the DebugInfo preview coordinate display in sync for normal tool use before the wall tool has been used.

Fixes

Closes #24

Verification

• npm ci could not run because the upstream package lock is out of sync with package.json (lucide-react@0.563.0 is missing from the lock file).
• npm install --no-package-lock
• npm run build -> succeeded with existing warnings.
• git diff --check

PayPal for bounty payout if accepted: aa.631@hotmail.com

[vercel]

@Da7-Tech is attempting to deploy a commit to the Hytopia Team on Vercel.

A member of the Team first needs to authorize it.

[Da7-Tech]

Local verification completed after opening the PR:

• npm run build succeeded.
• git diff --check passed.

The current Vercel failure appears to be the standard external contributor authorization gate, not a build failure from this branch.