Standardize PKR currency formatting across pricing and payment UI

[Taleef7]

Context

Pricing and payment pages currently format amounts with a mix of PKR {number.toLocaleString()} and landing-page string formatting. advisor_update.md calls out this polish item; consistent PKR formatting helps the public launch feel more trustworthy.

Acceptance criteria

• Add a small shared formatter for PKR amounts, likely using Intl.NumberFormat('en-PK', { style: 'currency', currency: 'PKR' }) or an intentional PKR 12,345 variant.
• Replace ad hoc amount formatting on landing, package selection, package detail, and admin payment pages.
• Confirm zero/placeholder pricing states still render clearly when env values are missing.
• Add a focused unit test for the formatter if introduced.

References

• advisor_update.md UX / polish: PKR formatting
• lib/config/pricing.ts
• app/page.tsx
• app/dashboard/packages/new/page.tsx
• app/dashboard/packages/[id]/page.tsx
• app/admin/payments/page.tsx