feat: add Prism background to landing hero section

[0xEmberZz]

Summary

• Add Prism component from react-bits registry (WebGL animated prism background)
• Replace hero background with animated Prism effect
• Redesign hero layout with full-height mascot on right side
• Add eliza landing page sections
• Configure shadcn with react-bits registry

Test plan

• Verify Prism animation renders correctly on landing page
• Check responsive layout on mobile and desktop
• Confirm mascot image displays full-height on right side

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[cla-assistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

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Zhou seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}