Fix/broken links

[0xward]

Description

This pull request resolves broken links found in the README.md and stacking.md files to improve documentation accuracy.

1. Motivation for change: Several links were pointing to deprecated domains or incorrect repositories, resulting in 404 errors.
2. What was changed:
   • Updated the PoX consensus link in README.md.
   • Updated the SIP-007 link in stacking.md to the correct repository.
   • Fixed the malformed Google Sheets URL in stacking.md.
3. How does this impact application developers: Improves documentation reliability and ensures access to correct specifications.
4. Link to relevant issues and documentation: Addresses broken links in README.md and stacking.md.

Type of Change

• API reference/documentation update

Does this introduce a breaking change?

No.

Are documentation updates required?

• Link to documentation updates: N/A (This PR is the documentation update)

Testing information

1. Is testing required for this change? No.
2. If it’s a bug fix, list steps to reproduce the bug: N/A
3. Briefly mention affected code paths: N/A (Documentation changes only).
4. List other affected projects if possible: N/A
5. Things to watch out for when testing: Verified links redirect to expected pages.

Checklist

• Code is commented where needed (N/A)
• Unit test coverage for new or modified code paths (N/A)
• npm run test passes (N/A)
• Changelog is updated

[CLAassistant]

All committers have signed the CLA.