Replace SendGrid with Mailjet

[cherylli]

What do we need to build or fix?
We need to remove SendGrid and replace it with Mailjet in our email API. SendGrid has caused various issues over the years, including deliverability and reliability problems, and these have gotten worse recently. We're switching to Mailjet for a simpler and more stable setup.

Technical details

• Update pages/api/sendEmail.js to use Mailjet instead of SendGrid.
• No templates are needed—this should be a basic transactional email.
• After a user submits the contact form, Mailjet should send the email to hello@webdevpath.co (use your own email during development)
• Developer should use their own Mailjet accounts for development and testing.

Approach suggestions

• Remove any SendGrid-specific imports and config.
• Use Mailjet Send API v3.1.
• Ensure the request payload includes subject, sender, recipient, and form body content.
• Make sure error handling returns appropriate HTTP status codes to the client.

Deadline
Please keep in mind that once you assign this task to yourself, you'll need to complete it in 10 days.

Acceptance criteria

• Test the section and components in many screen sizes, you can use the Inspect tool for that.
• After a user submits the contact form, Mailjet should send the email to hello@webdevpath.co
• Test the feature in many browsers, such as Chrome, Firefox, Edge, and Safari (MAC).
• If there are any build problems when submitting your PR, run yarn build locally to solve the issues and commit the changes.
• Update the CHANGELOG.md file.