Foundations: Replace calculator demo project link with corrected version

[G-O-T-W]

Because

The previously linked calculator project had a display overflow issue when users entered long sequences of digits without using operators. Additionally, it did not handle double operator presses correctly, which contradicts the updated project instructions.

This PR

• Replaces the old calculator demo link with a new one that:
  • Prevents display overflow when entering long numbers.
  • Handles consecutive operator inputs properly, matching updated requirements.
  • Fully adheres to the project's functional expectations.

Issue

Closes #29322

Additional Information

This update improves the quality and reliability of the demo for learners, ensuring the example aligns with the behavior expected by the curriculum's instructions.

Pull Request Requirements

• I have thoroughly read and understand The Odin Project curriculum contributing guide
• The title of this PR follows the location of change: brief description of change format, e.g. Intro to HTML and CSS lesson: Fix link text
• The Because section summarizes the reason for this PR
• The This PR section has a bullet point list describing the changes in this PR
• If this PR addresses an open issue, it is linked in the Issue section
• If any lesson files are included in this PR, they have been previewed with the Markdown preview tool to ensure it is formatted correctly
• If any lesson files are included in this PR, they follow the Layout Style Guide

[KevinMulhern]

Thanks @G-O-T-W