Adds the merchant surface on Base: create payment links and itemized
invoices, publish subscription offers, read the dashboard, manage API keys
and signed webhooks. Adds the payer side too, so an agent can settle a link
or invoice in USDC on-chain and manage its own subscriptions.
Funds settle to the QIAN_KEY wallet, which signs a short-lived session. The
subscribe approval covers three periods rather than an unlimited amount.
Comments trimmed to one-liners before publish.
Qian