Tokenized auto-pay: Razorpay

[Panelica]

Part of the tokenized auto-pay epic #34. help-wanted — independent contributor task.

Implement the Tokenizable capability for Razorpay so a customer's stored card is auto-charged when a renewal invoice is generated:

• Save card: Save a card token and charge it off-session, and persist the reusable token in payment_methods.remote_token (+ brand/last4/expiry for display).
• Off-session charge: charge the stored token for a renewal Invoice with no customer interaction, then let the core mark the invoice paid + activate the service.
• Follow the capability contract and the Stripe reference implementation (Tokenized auto-pay: Stripe (SetupIntent + off_session) — reference implementation #35) exactly. Keep PNLCS invoicing as the single source of truth — do not wire Razorpay's native subscription product.
• On decline / 3-D Secure required, return a failure the core can hand to dunning (notify the customer to pay manually).

Module: modules/Gateways/Razorpay/RazorpayModule.php. isTokenised() currently returns false — flip it to true as part of this task.
Docs: Razorpay Tokens / recurring payments API.

⚠️ Blocked on #35 — the gateway capability contract lands there with the Stripe reference. Please wait for it (or coordinate on the epic #34) before starting, so you build against the final contract. Comment on #34 to claim this gateway.