feat: add mollie.js helper and embedded checkout API call

lib/api/billing.ts

@@ -101,3 +101,19 @@ export interface Order {
 export async function getOrders(): Promise<Order[]> {
   return apiRequest<Order[]>('/api/billing/invoices')
 }
+
+export interface CreateEmbeddedCheckoutParams {
+  plan_id: string
+  interval: string
+  limit: number
+  country: string
+  vat_id?: string
+  card_token: string
+}
+
+export async function createEmbeddedCheckout(params: CreateEmbeddedCheckoutParams): Promise<{ status: 'success' | 'pending'; redirect_url?: string }> {
+  return apiRequest<{ status: 'success' | 'pending'; redirect_url?: string }>('/api/billing/checkout-embedded', {
+    method: 'POST',
+    body: JSON.stringify(params),
+  })
+}

lib/mollie.ts

@@ -0,0 +1,69 @@
+'use client'
+
+// Mollie.js types (no official @types package)
+export interface MollieInstance {
+  createComponent: (type: string, options?: { styles?: Record<string, unknown> }) => MollieComponent
+  createToken: () => Promise<{ token: string | null; error: MollieError | null }>
+}
+
+export interface MollieComponent {
+  mount: (selector: string | HTMLElement) => void
+  unmount: () => void
+  addEventListener: (event: string, callback: (event: unknown) => void) => void
+}
+
+export interface MollieError {
+  field: string
+  message: string
+}
+
+declare global {
+  interface Window {
+    Mollie: (profileId: string, options?: { locale?: string; testmode?: boolean }) => MollieInstance
+  }
+}
+
+const MOLLIE_PROFILE_ID = process.env.NEXT_PUBLIC_MOLLIE_PROFILE_ID || ''
+
+// Mollie Components card field styles — matches Pulse dark theme
+export const MOLLIE_FIELD_STYLES = {
+  base: {
+    color: '#ffffff',
+    fontSize: '14px',
+    fontFamily: '-apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif',
+    fontWeight: '400',
+    letterSpacing: '0.025em',
+    '::placeholder': {
+      color: '#737373',
+    },
+  },
+  valid: {
+    color: '#ffffff',
+  },
+  invalid: {
+    color: '#ef4444',
+  },
+}
+
+let mollieInstance: MollieInstance | null = null
+
+/**
+ * Initialize Mollie.js. Must be called after the Mollie script has loaded.
+ */
+export function initMollie(): MollieInstance | null {
+  if (mollieInstance) return mollieInstance
+  if (typeof window === 'undefined' || !window.Mollie || !MOLLIE_PROFILE_ID) return null
+
+  // Mollie auto-detects test/live mode based on the API key configured server-side.
+  mollieInstance = window.Mollie(MOLLIE_PROFILE_ID, {
+    locale: 'en_US',
+  })
+  return mollieInstance
+}
+
+/**
+ * Get the current Mollie instance (must call initMollie first).
+ */
+export function getMollie(): MollieInstance | null {
+  return mollieInstance
+}