Add --verbose flag for real-time file discovery feedback

Implement verbose mode that shows files as they are discovered during
collection rather than just a summary. This provides better user feedback
during the typically slow filesystem traversal phase.

Features:
- Real-time "found: filename" output as files are discovered
- Verbose feedback during collection phase (not archiving phase)
- Simple, focused output that shows filtering effects
- Helps users track progress during potentially slow operations

Changes:
- Add --verbose boolean flag to CLI
- Pass verbose flag to collector constructors
- Display "found: filename" output during file collection
- Add test case to verify verbose output contains expected messages
- Update test suite with helper function to verify output contents

collector/collector.go

@@ -18,21 +18,24 @@ type FileEntry struct {
 type Collector struct {
 	matcher   Matcher
 	dirFilter DirectoryFilter
+	verbose   bool
 }
 
 // New creates a new collector with the specified matcher
-func New(matcher Matcher) *Collector {
+func New(matcher Matcher, verbose bool) *Collector {
 	return &Collector{
 		matcher:   matcher,
 		dirFilter: nil,
+		verbose:   verbose,
 	}
 }
 
 // NewWithDirectoryFilter creates a new collector with the specified matcher and directory filter
-func NewWithDirectoryFilter(matcher Matcher, dirFilter DirectoryFilter) *Collector {
+func NewWithDirectoryFilter(matcher Matcher, dirFilter DirectoryFilter, verbose bool) *Collector {
 	return &Collector{
 		matcher:   matcher,
 		dirFilter: dirFilter,
+		verbose:   verbose,
 	}
 }
 
@@ -98,6 +101,11 @@ func (c *Collector) Collect(sourceDir string) ([]FileEntry, error) {
 			// Clean the relative path to ensure consistent formatting
 			relPath = filepath.ToSlash(relPath)
 
+			// Show verbose output when file is found
+			if c.verbose {
+				fmt.Printf("found: %s\n", relPath)
+			}
+
 			files = append(files, FileEntry{
 				Path:     relPath,
 				FullPath: path,