Invoices

Scopes invoices:read / invoices:write.

• GET /api/v1/invoices
• POST /api/v1/invoices — create draft
• GET /api/v1/invoices/:id
• POST /api/v1/invoices/:id/send — draft → sent

No mark-paid via API key — buyers pay on Bruce.

MCP: bruce_invoice_create, bruce_invoice_send, bruce_invoice_list.