fix: implement proper pattern matching for .devpodignore files

[haroondilshad]

Fix .devpodignore Pattern Matching Bug

Problem

The .devpodignore file was not properly excluding files during workspace uploads. Despite having patterns like **/node_modules or *.log, the upload size remained unexpectedly large because the exclusion logic in pkg/extract/compress.go was using simple strings.HasPrefix matching instead of proper glob pattern matching.

Root Cause

The isExcluded function in pkg/extract/compress.go was performing basic string prefix checks rather than using the github.com/moby/patternmatcher library that properly handles .devpodignore syntax (which follows .dockerignore conventions).

Solution

• Enhanced Archiver struct: Added patternMatcher field to store compiled patterns
• Updated NewArchiver: Initialize pattern matcher when exclusion patterns are provided
• Fixed isExcluded function:
  • Use patternMatcher.MatchesOrParentMatches() for proper glob pattern evaluation
  • Handle cross-platform path normalization with filepath.ToSlash
  • Maintain backwards compatibility with fallback to old prefix matching behavior

What This Enables

• ✅ Recursive wildcards: **/node_modules correctly ignores nested node_modules directories
• ✅ File extensions: *.log, *.tmp properly exclude files by extension
• ✅ Complex patterns: **/.git, **/dist, *.{png,jpg} work as expected
• ✅ Monorepo support: Patterns handle nested project structures correctly
• ✅ Character classes: [!.]*/ and other advanced patterns are supported

Testing

Added comprehensive unit tests in pkg/extract/compress_test.go following the project's testing methodology:

• TestArchiver_isExcluded: Table-driven tests for various pattern scenarios
• TestWriteTarExclude_PatternMatching: End-to-end tar exclusion verification
• TestWriteTarExclude_BackwardsCompatibility: Ensures existing behavior is preserved
• TestNewArchiver_PatternMatcherCreation: Tests pattern matcher initialization

Impact

This fix should significantly reduce workspace upload times and sizes for users with properly configured .devpodignore files, especially in monorepo setups with patterns like **/node_modules, **/dist, etc.

Backwards Compatibility

The implementation includes a fallback mechanism that preserves the old strings.HasPrefix behavior if pattern matching fails, ensuring no regressions for existing setups.