[Components] netcore

# netcore
## URLs
## Webhook Sources
### new-email-instant
#### Description
Emit new event when a new email is received in Netcore. Users can specify optional filters such as sender address, subject keywords, or recipient.
### new-subscriber-instant
#### Description
Emit new event when a new subscriber is added to a mailing list in Netcore. Users must specify the mailing list ID.
### email-status-updated-instant
#### Description
Emit new event when an email status is updated (e.g., delivered, opened, clicked, bounced). Users can filter by email campaign or status type.
## Actions
### send-email
#### Description
Send an email via Netcore. Users must provide sender address, recipient(s), subject, and body content. Optionally, they can include attachments and custom headers.
### add-subscriber
#### Description
Add a new subscriber to a mailing list in Netcore. Users must specify the mailing list ID and subscriber email. Optionally, they can include name and custom attributes.
### create-email-campaign
#### Description
Create a new email campaign in Netcore. Users must provide the campaign name, sender details, and email content. Optionally, they can specify segmentation rules and scheduling options.

The issue covers a new Netcore integration with three webhook sources and three actions, including new-email-instant, send-email, and create-email-campaign. No files, tests, URLs, or entry points are named, so first locate the existing component structure and comparable integrations; done means implementing and validating all listed sources and actions.

Written by the indexing model from the issue text.