feat: add ignoreFileExtensions option

[rainerhahnekamp]

Adds the possbility to ignore files based on their extension and comes with a default of common files that should be ignored.

Fixes

• RFC: Allow to exclude files via "file extensions" #216
• Eslint throws errors for css/svg imports in a React + sheriff app #215
• Vuejs Integration #159

[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

[Copilot]

Pull Request Overview

This PR adds an ignoreFileExtensions configuration option to Sheriff, enabling users to specify which file extensions should be ignored during import traversal. This addresses performance issues caused by processing non-code files and provides flexibility for project-specific configurations.

• Introduces the ignoreFileExtensions configuration option with sensible defaults for common non-code files
• Updates the filesystem traversal logic to skip files with ignored extensions early in the process
• Adds comprehensive test coverage and documentation for the new feature

Reviewed Changes

Copilot reviewed 21 out of 21 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
packages/core/src/lib/config/default-file-extensions.ts	Defines default list of file extensions to ignore (images, styles, fonts, etc.)
packages/core/src/lib/config/user-sheriff-config.ts	Adds the ignoreFileExtensions property to the user configuration interface
packages/core/src/lib/config/parse-config.ts	Implements parsing logic for the new configuration option with function/array support
packages/core/src/lib/file-info/traverse-filesystem.ts	Updates filesystem traversal to skip files with ignored extensions
packages/core/src/lib/file-info/generate-unassigned-file-info.ts	Passes ignore extensions parameter through the traversal chain
test-projects/angular-iv/tests/	Adds integration tests to verify ignored extensions functionality
docs/	Adds comprehensive documentation and release notes for the new feature

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[Copilot]

The function getIgnoreFileExtensions lacks documentation. Consider adding a JSDoc comment explaining its purpose, parameters, and return value, especially since it handles both array and function inputs for the configuration option.

Suggested change

	/**
	* Returns a normalized array of file extensions to ignore.
	*
	* @param ignoreFileExtensions - Either an array of file extensions to ignore,
	* or a function that receives the default ignore list and returns a new array.
	* @returns A deduplicated, lowercased array of file extensions to ignore.
	*/

[Copilot]

The file extension extraction logic using split('.').pop() could fail for files without extensions or complex filenames. Consider using a more robust approach like path.extname() from Node.js or add validation to handle edge cases like files starting with dots or multiple dots.

Suggested change

	const fileExtension = fileName.split('.').pop()?.toLowerCase();
	const fileExtension = path.extname(fileName).toLowerCase().replace(/^\./, '');