[Feature] Add Links to JSON Schema in Import Dialog

[lightyoruichi]

Is there an existing issue for this feature?

• Yes, I have searched the existing issues and it doesn't exist.

Feature Description

Description
As a user, when I select .json files as the file type in the Import Dialog, I would like to see clickable links to the JSON schema documentation. This would allow me to reference the correct file format with both the official schema on GitHub and the user-friendly presentation on [jsonresume.org](https://jsonresume.org/schema).

Proposed Solution
Update the helper text for the .json file type to include two clickable links:

1. GitHub: https://github.com/jsonresume/resume-schema/blob/master/schema.json
   For users who need direct access to the schema file.
2. JsonResume.org: https://jsonresume.org/schema
   For users who prefer a user-friendly overview of the schema.

Ensure both links are styled for accessibility (e.g., target="_blank" and rel="noopener noreferrer") and clearly indicate their purpose.

Acceptance Criteria

• The helper text for .json files includes both hyperlinks (GitHub and JsonResume.org).
• Links open in a new browser tab.
• Text clearly identifies each link for its intended audience (e.g., "GitHub schema" and "JsonResume.org schema").
• Feature is tested for accessibility and functionality.

Example Text for Helper Message

Accepts only .json files. See the schema documentation:

• [GitHub schema](https://github.com/jsonresume/resume-schema/blob/master/schema.json)
• [JsonResume.org schema](https://jsonresume.org/schema)

Additional Context
Providing both links ensures users have flexibility to choose between a developer-centric view (GitHub) and a more accessible overview (JsonResume.org). This reduces confusion and errors during the import process while improving overall usability.