Add godoc strings to all exported types, functions, and fields

Documents:
- cli: NO_COLOR, RunOptions fields, CLIApp, VersionString
- checker: Result fields, Status constants, CheckStatus fields
- scanner: EnumerateStatus, ScanStatus, Options, FileEntry fields
- log: Level alias, DisableStyling, Init, Info/Debug functions,
  verbosity helpers, GetLogger, GetLevel, WithError
- mfer: ManifestScanOptions, New, NewFromPaths, NewFromFS, MAGIC

internal/scanner/scanner.go

@@ -21,8 +21,8 @@ import (
 
 // EnumerateStatus contains progress information for the enumeration phase.
 type EnumerateStatus struct {
-	FilesFound int64
-	BytesFound int64
+	FilesFound int64 // Number of files discovered so far
+	BytesFound int64 // Total size of discovered files (from stat)
 }
 
 // Phase 2: Scan (ToManifest)
@@ -32,27 +32,27 @@ type EnumerateStatus struct {
 
 // ScanStatus contains progress information for the scan phase.
 type ScanStatus struct {
-	TotalFiles   int64
-	ScannedFiles int64
-	TotalBytes   int64
-	ScannedBytes int64
-	BytesPerSec  float64
+	TotalFiles   int64   // Total number of files to scan
+	ScannedFiles int64   // Number of files scanned so far
+	TotalBytes   int64   // Total bytes to read (sum of all file sizes)
+	ScannedBytes int64   // Bytes read so far
+	BytesPerSec  float64 // Current throughput rate
 }
 
 // Options configures scanner behavior.
 type Options struct {
-	IgnoreDotfiles bool
-	FollowSymLinks bool
-	Fs             afero.Fs // Filesystem to use, defaults to OsFs
+	IgnoreDotfiles bool     // Skip files and directories starting with a dot
+	FollowSymLinks bool     // Resolve symlinks instead of skipping them
+	Fs             afero.Fs // Filesystem to use, defaults to OsFs if nil
 }
 
 // FileEntry represents a file that has been enumerated.
 type FileEntry struct {
-	Path    string // Relative path (used in manifest)
-	AbsPath string // Absolute path (used for reading file content)
-	Size    int64
-	Mtime   time.Time
-	Ctime   time.Time
+	Path    string    // Relative path (used in manifest)
+	AbsPath string    // Absolute path (used for reading file content)
+	Size    int64     // File size in bytes
+	Mtime   time.Time // Last modification time
+	Ctime   time.Time // Creation time (platform-dependent)
 }
 
 // Scanner accumulates files and generates manifests from them.