feat(api): 🎉 Add business profile and catalog management

* Implement endpoints for managing business profiles:
  - Get business profile
  - Update business profile

* Add catalog management features:
  - List catalogs
  - List products in a catalog
  - Send catalog messages
  - Send single product messages
  - Send product list messages

* Introduce media upload functionality for sending media files.

* Add flow management capabilities:
  - Deprecate flows

* Update API documentation to reflect new endpoints and features.

pkg/whatsapp/businessapi/profile.go

@@ -0,0 +1,28 @@
+package businessapi
+
+import (
+	"context"
+	"net/url"
+)
+
+// GetBusinessProfile retrieves the business profile for this phone number.
+func (c *Client) GetBusinessProfile(ctx context.Context) (*BusinessProfile, error) {
+	params := url.Values{
+		"fields": {"about,address,description,email,websites,vertical,profile_picture_url"},
+	}
+
+	var resp BusinessProfile
+	if err := c.graphAPIGet(ctx, c.config.PhoneNumberID+"/whatsapp_business_profile", params, &resp); err != nil {
+		return nil, err
+	}
+	return &resp, nil
+}
+
+// UpdateBusinessProfile updates one or more business profile fields.
+// Only include fields you want to change — omitted fields are left untouched.
+func (c *Client) UpdateBusinessProfile(ctx context.Context, profile BusinessProfileUpdate) error {
+	profile.MessagingProduct = "whatsapp"
+
+	var resp map[string]any
+	return c.graphAPIPost(ctx, c.config.PhoneNumberID+"/whatsapp_business_profile", profile, &resp)
+}