IAV-848/feat(integrations): add Shopify & WooCommerce credential mappings + remove unused imports

Summary

This MR extends the N8N credential type mapping table with support for two new e-commerce platforms — Shopify and WooCommerce — and cleans up dead import statements in UserIntegrationServiceImpl.

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Changes

AgentIntegrationServiceImpl

Two new entries added to the static CREDENTIAL_TYPE_MAPPINGS map under a new // E-commerce / CMS section:

Internal Enum	N8N Type
SHOPIFY_ACCESS_TOKEN	shopifyAccessTokenApi
WOOCOMMERCE	wooCommerceApi

These mappings are required for correct credential creation and workflow binding when agents integrate with Shopify or WooCommerce via N8N. Without them, the fallback camelCase conversion would produce incorrect type names (e.g. shopifyaccesstokenApi instead of shopifyAccessTokenApi).

UserIntegrationServiceImpl

Removed three imports that were no longer referenced in the class body:

• lombok.SneakyThrows
• com.izemx.iavia.dtos.n8n.CredentialInfoResponse
• java.util.stream.Collectors

No behavioral changes.

Related Issues

IAV-848