feat: add support for .al (AL Language) file extension with fallback chunking

[roomote]

Summary

This PR attempts to address Issue #8596 by adding support for .al (AL Language) file extensions used in Microsoft Dynamics 365 Business Central development.

Changes

• Added "al" to the extensions array in src/services/tree-sitter/index.ts
• Added ".al" to the fallbackExtensions array in src/services/code-index/shared/supported-extensions.ts with appropriate comment

Implementation Details

The .al files will be:

• Recognized as supported file extensions
• Included in codebase scanning and indexing
• Processed using fallback chunking (length-based) instead of tree-sitter parsing since no dedicated WASM parser exists
• Searchable through codebase retrieval features
• Available in context for AI assistance

Testing

• Verified code-index tests pass successfully
• No regressions introduced
• Changes follow existing patterns for languages without dedicated parsers (e.g., Visual Basic .NET, Scala, Swift)

Fixes #8596

Feedback and guidance are welcome!

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Important

Adds support for .al files with fallback chunking in index.ts and supported-extensions.ts.

• Behavior:
  • Adds support for .al (AL Language) files in index.ts and supported-extensions.ts.
  • .al files are indexed and processed using fallback chunking due to lack of a dedicated parser.
• Testing:
  • Verified code-index tests pass.
  • No regressions introduced.
  • Consistent with handling of other languages without dedicated parsers.

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[roomote]

No new issues found - the implementation correctly follows the established pattern for adding fallback extensions. The changes are minimal, well-documented, and consistent with existing code.

[yavpungggi]

Opened new PR #8606 with the branch from roomote, but added test parser.vb.spec

@hannesrudolph can be closed