Add manual credit granting to the dashboard

Merged
ST
15d ago
+782-69

Stacked on #15405, which adds the endpoint this calls.

Lets a merchant add credits to a customer's meter from the dashboard.

Screenshots
Modal
Screenshot 2026-10-13 at 22 59 24
Button on each customer meter rows
Screenshot 2026-10-13 at 22 58 27
Customer Meter page -- Add credit button
Screenshot 2026-10-13 at 22 58 14