docs: replace privacy and terms placeholders

[saurabhhhcodes]

Summary

• Replaces placeholder Privacy Policy copy with product-specific sections for Clerk, Supabase, OpenAI, Razorpay, retention, deletion, and user choices
• Replaces placeholder Terms of Service copy with acceptable use, account, Pro billing, AI output, availability, and contact terms
• Keeps the existing page layout and support email intact

Validation

• git diff --check
• pnpm lint (passes with one pre-existing warning in app/page.tsx about an unused Button import)
• tsc --noEmit

next build --webpack is blocked locally by native optional dependency loading for @next/swc-darwin-arm64 / lightningcss.darwin-arm64.node in this macOS environment, before these pages are compiled.

Fixes #12

Suggested GSSoC labels

• gssoc:approved
• level:beginner
• quality:clean
• type:docs

[vercel]

@saurabhhhcodes is attempting to deploy a commit to the notsoocool's projects Team on Vercel.

A member of the Team first needs to authorize it.

[saurabhhhcodes]

Quick follow-up: this PR is still mergeable from GitHub's side and the linked issue #12 already carries gssoc:approved plus level:beginner. If there are no remaining changes needed, please review and merge when convenient.