🔁 Handle subscription.resumed — restore ACTIVE status

Context

docs/DEPLOYMENT.md instructs enabling the subscription.resumed Razorpay webhook event, but STATUS_MAP in handleRazorpaySubscriptionEvent (src/lib/commerce/subscriptions.ts) has no entry for it — resuming a paused/halted subscription updates nothing locally, so the Subscription row stays PAUSED/PAST_DUE while Razorpay bills again.

Implementation

1. Add "subscription.resumed": "ACTIVE" to STATUS_MAP; when transitioning PAST_DUE/PAUSED → ACTIVE, recompute currentPeriodStart/End from the event payload's charge fields (mirror the subscription.charged period logic) so access windows don't silently extend.
2. If the resume event carries no billing-cycle info, rely on the paired subscription.charged that Razorpay emits on the next cycle; resumed should still flip status immediately.
3. Reuse the lapse/reinstate helper used by activated so enrollments scoped by Enrollment.subscriptionId regain access exactly once (idempotent).
4. Add a unit test with a synthetic resumed payload.

Acceptance

• Resuming in Razorpay dashboard flips local status to ACTIVE and restores scoped enrollments
• No duplicate credit grants or period extension

Part of #38. Advances #42.

Start in src/lib/commerce/subscriptions.ts at handleRazorpaySubscriptionEvent and compare the existing activated and subscription.charged handling, including the lapse/reinstate helper. Add coverage with a synthetic subscription.resumed payload; done means the subscription becomes ACTIVE, scoped enrollments regain access once, and billing periods or credits are not duplicated.