Fix zoom in 3d view

[imrishabh18]

The zoom shouldn't always be happening at the centre of the board, it should rather be happening where the cursor/pointer is at

/bounty $20

[algora-pbc]

💎 $20 bounty • tscircuit

Steps to solve:

1. Start working: Comment /attempt #493 with your implementation plan
2. Submit work: Create a pull request including /claim #493 in the PR body to claim the bounty
3. Receive payment: 100% of the bounty is received 2-5 days post-reward. Make sure you are eligible for payouts

❗ Important guidelines:

• Join our discord to get support from other contributors
• Links: tscircuit docs · tscircuit playground
• To claim a bounty for UI, you need to provide a short demo video of your changes in your pull request
• Do not ask to be assigned unless you've contributed before

Thank you for contributing to tscircuit/3d-viewer!

Attempt	Started (UTC)	Solution	Actions
🟢 @dhvll	Sep 17, 2025, 10:39:41 AM	#494	Reward
🟢 @MustafaMulla29	Sep 18, 2025, 03:29:29 PM	#496	Reward

[dhvll]

/attempt #493

[algora-pbc]

🎉🎈 @MustafaMulla29 has been awarded $20 by tscircuit! 🎈🎊