fix: Add JSX and TSX file support to ast-grep scanner

[loleek]

Summary

• Add JSX and TSX language mapping in detectLangFromRuleID function (scanner/astgrep.go:198-201)
• Improve TypeScript rules to use kind: import_statement for better accuracy
• Add arrow_function support to function detection
• Create dedicated rule files for JSX and TSX languages

Problem

Codemap was unable to properly scan React/TypeScript projects that use .jsx and .tsx file extensions, as these file types were not recognized in the ast-grep language detection
logic.

Solution

This PR adds support for JSX and TSX files by:

1. Mapping tsx → typescript and jsx → javascript in the language detector
2. Creating dedicated ast-grep rule files for both JSX and TSX
3. Refining TypeScript import rules to use AST kind matching instead of patterns

Test plan

• Test scanning a React project with .jsx files
• Test scanning a TypeScript React project with .tsx files
• Verify import detection works correctly with the new kind: import_statement rule
• Confirm arrow functions are detected properl