chore: modernize workflows, security scanning, and linting configuration (#50)

* build: update Go 1.25, CI workflows, and build tooling

- Upgrade to Go 1.25
- Add benchmark targets to Makefile
- Implement parallel gosec execution
- Lock tool versions for reproducibility
- Add shellcheck directives to scripts
- Update CI workflows with improved caching

* refactor: migrate from golangci-lint to revive

- Replace golangci-lint with revive for linting
- Configure comprehensive revive rules
- Fix all EditorConfig violations
- Add yamllint and yamlfmt support
- Remove deprecated .golangci.yml

* refactor: rename utils to shared and deduplicate code

- Rename utils package to shared
- Add shared constants package
- Deduplicate constants across packages
- Address CodeRabbit review feedback

* fix: resolve SonarQube issues and add safety guards

- Fix all 73 SonarQube OPEN issues
- Add nil guards for resourceMonitor, backpressure, metricsCollector
- Implement io.Closer for headerFileReader
- Propagate errors from processing helpers
- Add metrics and templates packages
- Improve error handling across codebase

* test: improve test infrastructure and coverage

- Add benchmarks for cli, fileproc, metrics
- Improve test coverage for cli, fileproc, config
- Refactor tests with helper functions
- Add shared test constants
- Fix test function naming conventions
- Reduce cognitive complexity in benchmark tests

* docs: update documentation and configuration examples

- Update CLAUDE.md with current project state
- Refresh README with new features
- Add usage and configuration examples
- Add SonarQube project configuration
- Consolidate config.example.yaml

* fix: resolve shellcheck warnings in scripts

- Use ./*.go instead of *.go to prevent dash-prefixed filenames
  from being interpreted as options (SC2035)
- Remove unreachable return statement after exit (SC2317)
- Remove obsolete gibidiutils/ directory reference

* chore(deps): upgrade go dependencies

* chore(lint): megalinter fixes

* fix: improve test coverage and fix file descriptor leaks

- Add defer r.Close() to fix pipe file descriptor leaks in benchmark tests
- Refactor TestProcessorConfigureFileTypes with helper functions and assertions
- Refactor TestProcessorLogFinalStats with output capture and keyword verification
- Use shared constants instead of literal strings (TestFilePNG, FormatMarkdown, etc.)
- Reduce cognitive complexity by extracting helper functions

* fix: align test comments with function names

Remove underscores from test comments to match actual function names:
- benchmark/benchmark_test.go (2 fixes)
- fileproc/filetypes_config_test.go (4 fixes)
- fileproc/filetypes_registry_test.go (6 fixes)
- fileproc/processor_test.go (6 fixes)
- fileproc/resource_monitor_types_test.go (4 fixes)
- fileproc/writer_test.go (3 fixes)

* fix: various test improvements and bug fixes

- Remove duplicate maxCacheSize check in filetypes_registry_test.go
- Shorten long comment in processor_test.go to stay under 120 chars
- Remove flaky time.Sleep in collector_test.go, use >= 0 assertion
- Close pipe reader in benchmark_test.go to fix file descriptor leak
- Use ContinueOnError in flags_test.go to match ResetFlags behavior
- Add nil check for p.ui in processor_workers.go before UpdateProgress
- Fix resource_monitor_validation_test.go by setting hardMemoryLimitBytes directly

* chore(yaml): add missing document start markers

Add --- document start to YAML files to satisfy yamllint:
- .github/workflows/codeql.yml
- .github/workflows/build-test-publish.yml
- .github/workflows/security.yml
- .github/actions/setup/action.yml

* fix: guard nil resourceMonitor and fix test deadlock

- Guard resourceMonitor before CreateFileProcessingContext call
- Add ui.UpdateProgress on emergency stop and path error returns
- Fix potential deadlock in TestProcessFile using wg.Go with defer close

fileproc/registry.go

@@ -5,6 +5,8 @@ import (
 	"path/filepath"
 	"strings"
 	"sync"
+
+	"github.com/ivuorinen/gibidify/shared"
 )
 
 const minExtensionLength = 2
@@ -52,9 +54,9 @@ func initRegistry() *FileTypeRegistry {
 		imageExts:    getImageExtensions(),
 		binaryExts:   getBinaryExtensions(),
 		languageMap:  getLanguageMap(),
-		extCache:     make(map[string]string, 1000),        // Cache for extension normalization
-		resultCache:  make(map[string]FileTypeResult, 500), // Cache for type results
-		maxCacheSize: 500,
+		extCache:     make(map[string]string, shared.FileTypeRegistryMaxCacheSize),
+		resultCache:  make(map[string]FileTypeResult, shared.FileTypeRegistryMaxCacheSize),
+		maxCacheSize: shared.FileTypeRegistryMaxCacheSize,
 	}
 }
 
@@ -63,25 +65,28 @@ func getRegistry() *FileTypeRegistry {
 	registryOnce.Do(func() {
 		registry = initRegistry()
 	})
+
 	return registry
 }
 
-// GetDefaultRegistry returns the default file type registry.
-func GetDefaultRegistry() *FileTypeRegistry {
+// DefaultRegistry returns the default file type registry.
+func DefaultRegistry() *FileTypeRegistry {
 	return getRegistry()
 }
 
-// GetStats returns a copy of the current registry statistics.
-func (r *FileTypeRegistry) GetStats() RegistryStats {
+// Stats returns a copy of the current registry statistics.
+func (r *FileTypeRegistry) Stats() RegistryStats {
 	r.cacheMutex.RLock()
 	defer r.cacheMutex.RUnlock()
+
 	return r.stats
 }
 
-// GetCacheInfo returns current cache size information.
-func (r *FileTypeRegistry) GetCacheInfo() (extCacheSize, resultCacheSize, maxCacheSize int) {
+// CacheInfo returns current cache size information.
+func (r *FileTypeRegistry) CacheInfo() (extCacheSize, resultCacheSize, maxCacheSize int) {
 	r.cacheMutex.RLock()
 	defer r.cacheMutex.RUnlock()
+
 	return len(r.extCache), len(r.resultCache), r.maxCacheSize
 }
 
@@ -101,7 +106,9 @@ func normalizeExtension(filename string) string {
 func isSpecialFile(filename string, extensions map[string]bool) bool {
 	if filepath.Ext(filename) == "" {
 		basename := strings.ToLower(filepath.Base(filename))
+
 		return extensions[basename]
 	}
+
 	return false
 }