Issue Number: #728 [Enhancement: Add Robust Error Handling to /evershop/blob/main/packages/resend/api/resetPassword/[resetPassword]sendMail.js]

Summary

This PR enhances error handling and input validation in the [resetPassword]sendMail.js module. The goal is to prevent silent failures, improve logging, and provide clear user feedback when issues arise during the password reset email flow.

What is the current behavior?

• Silent failures may occur when required fields (email, token) or configuration variables (RESEND_API_KEY, resend.from) are missing or invalid.
• Errors in template reading, rendering, or email sending are not properly handled, potentially leading to no action taken or unclear responses.
• There is insufficient logging for debugging and error tracking.

What is the new behavior?

• Input validation ensures that email and token are present and valid before proceeding with the email flow.
• Configuration checks for missing RESEND_API_KEY and resend.from provide better error handling.
• Error handling for template rendering: If the template is invalid or fails to load, a fallback plain-text email is sent.
• Error handling for the email send process: Any failure in sending the email is logged and results in an appropriate HTTP error response.
• Improved logging captures meaningful context for all failure points, making debugging easier.
• Structured HTTP responses with clear, user-friendly error messages and correct status codes (400 for client errors and 500 for server errors).

PR Checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes/features)
• The code follows the existing project style and conventions
• The PR has appropriate documentation (if applicable)
• The changes are well-tested (manual testing in this case)

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no API changes)
• Build related changes
• CI related changes
• Other: Error-handling enhancement

Does this PR introduce a breaking change?

• ❌ No