One-time Paid Reports

[vishakh]

This PR adds one-time paid report runs, removes the 7-day subscription trial, and updates the app to run on the default Next 16/Turbopack path.

Changes

• Added one-time Stripe Checkout purchases for premium reports at $4.99 per run.
• Added report pass tracking via Stripe PaymentIntent metadata.
• Added /api/report-access to check and consume unused report passes.
• Added Dynamic JWT verification so consuming a paid report pass requires wallet ownership.
• Updated Analyze report cards to support either:
  • active subscription access,
  • promo access,
  • or a one-time paid report pass.
• Removed the 7-day Stripe subscription trial.
• Updated subscription and paywall copy to describe immediate $4.99/month billing.
• Added close confirmation for generated in-memory reports so users do not accidentally discard output.
• Migrated ESLint to flat config for ESLint 9.
• Updated Next to 16.2.10 and switched scripts from --webpack to default Turbopack.
• Added Turbopack aliases/shims for browser-incompatible dependencies.

Notes

• Existing Stripe trialing subscription handling remains in place so legacy trial subscriptions can still be checked or cancelled correctly.
• nilDB storage remains disabled during package migration.