chore: resolve broken and empty links across modelina documentation

[Ishita-190]

Fixes: #2408
A previous attempt to fix this issue (#2416) was blocked due to TypeScript errors in the netlify build preview

Description

Fixed all broken, empty, and outdated links throughout the Modelina documentation to improve user experience and navigation.

Changes Made

• docs/champions.md - Fixed empty anchor links for "Versioning and maintenance" and "Reviewing a PR"
• docs/constraints/README.md - Fixed broken link to internal-model.md
• docs/inputs/XSD.md - Fixed broken link to usage.md
• docs/internal-model.md - Fixed empty anchor link, added missing "The Splitting of Meta Models" section
• docs/languages/Java.md - Fixed broken integration.md link
• docs/languages/Rust.md - Added missing content sections, fixed table formatting, removed link functionality from empty links

 Implement `From<String> (serde_json)`
 Implement `Into<String> (serde_json)`
 Implement `From<FramedByteStream> (tokio_serde)`
 Implement `Into<FramedByteStream> (tokio_serde)`

• docs/other-tools.md - Fixed broken constrainer link
• Updated all constraint files to fix:
  Broken input-processing.md links
  Constants.ts links missing /master/ in path
  Files affected: CSharp, Cplusplus, Dart, Go, Java, JavaScript, Python, Rust, TypeScript
• docs/migrations/README.md - Updated migration links to absolute URLs
• docs/migrations/version-0-to-1.md - Fixed ConstrainedMetaModel, ConstrainedObjectPropertyModel, and ConstrainedEnumValueModel links
• docs/migrations/version-1-to-2.md - Fixed discriminator link and meta model link

Checklist

• The code follows the project's coding standards and is properly linted (npm run lint).
• Tests have been added or updated to cover the changes.
• Documentation has been updated to reflect the changes.
• All tests pass successfully locally.(npm run test).

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[Ishita-190]

@jonaslagoni I've made the changes you requested in the other PR for this issue, please take a look and let me know if any other changes need to be made.

[coveralls]

Pull Request Test Coverage Report for Build 21903770163

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 90.997%

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Totals
Change from base Build 21874638391:	0.0%
Covered Lines:	6942
Relevant Lines:	7421

---

💛 - Coveralls

[jonaslagoni]

When using code agents, always make sure you review your PR first :P

Remove PR_DESCRIPTION.md

[Ishita-190]

Ah that's embarrassing, I've removed it now. Thank you for pointing it out 😄

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[jonaslagoni]

This is incorrect.. Relative links in majority of the case should work (if they are docs) relatively on the website too :)

[Ishita-190]

Working on it, could you please confirm if this works?

function prepareContent(content, currentRelativePath = '/docs/README.md') { 
  content = content.replace('<!-- toc is generated with GitHub Actions do not remove toc markers -->', '');
  content = content.replace('<!-- toc -->', '');
  content = content.replace('<!-- tocstop -->', '');
  const normalizedCurrentPath = currentRelativePath.replace(/\\/g, '/');
  const currentDir = path.posix.dirname(normalizedCurrentPath);
  
  // Resolve relative links based on the current docs file path
  content = content.replace(/\]\(((?:\.\.\/|\.\/)[^)]+)\)/g, (fullMatch, relPath) => {
    const [, relativePathWithoutSuffix = relPath, suffix = ''] = relPath.match(/^([^?#]+)([?#].*)?$/) || [];
    const resolvedPath = path.posix.normalize(path.posix.join(currentDir, relativePathWithoutSuffix));
    if (/\.md$/i.test(relativePathWithoutSuffix)) {
      const docsPath = resolvedPath
        .replace(/\.md$/i, '')
        .replace(/\/README$/i, '')
        .toLowerCase();
      return `](${docsPath || '/docs'}${suffix})`;
    }
    return `](https://github.com/asyncapi/modelina/blob/master${resolvedPath}${suffix})`;
  });
  
  content = content.replace(/\]\(\/docs\/(.*?)README(?:\.md)?([^)]*)\)/gi, (fullMatch, folderPath, suffix) => {
    const normalizedFolderPath = folderPath.replace(/\/$/, '');
    return `](/docs/${normalizedFolderPath}${suffix})`;
  });

  // Use correct example links
  content = content.replace(/\]\((.*?)examples\/(.*?)\/?\)/g, '](/examples?selectedExample=$2)');
  content = content.replace('/examples?selectedExample=integrate-with-react', 'https://github.com/asyncapi/modelina/tree/master/examples/integrate-with-react');
  content = content.replace('/examples?selectedExample=integrate-with-next', 'https://github.com/asyncapi/modelina/tree/master/examples/integrate-with-next');
  content = content.replace('/examples?selectedExample=integrate-with-maven', 'https://github.com/asyncapi/modelina/tree/master/examples/integrate-with-maven');

  // Replace all references to local images for docs
  content = content.replace(/"(.*?)\/img\/(.*?)"/g, '"/img/docs/$2"');

  return content;
}