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/cli/entry.go

@@ -7,6 +7,8 @@ import (
 	"github.com/spf13/afero"
 )
 
+// NO_COLOR disables colored output when set. Automatically true if the
+// NO_COLOR environment variable is present (per https://no-color.org/).
 var NO_COLOR bool
 
 func init() {
@@ -17,15 +19,16 @@ func init() {
 }
 
 // RunOptions contains all configuration for running the CLI application.
+// Use DefaultRunOptions for standard CLI execution, or construct manually for testing.
 type RunOptions struct {
-	Appname string
-	Version string
-	Gitrev  string
-	Args    []string
-	Stdin   io.Reader
-	Stdout  io.Writer
-	Stderr  io.Writer
-	Fs      afero.Fs
+	Appname string    // Application name displayed in help and version output
+	Version string    // Version string (typically set at build time)
+	Gitrev  string    // Git revision hash (typically set at build time)
+	Args    []string  // Command-line arguments (typically os.Args)
+	Stdin   io.Reader // Standard input stream
+	Stdout  io.Writer // Standard output stream
+	Stderr  io.Writer // Standard error stream
+	Fs      afero.Fs  // Filesystem abstraction for file operations
 }
 
 // DefaultRunOptions returns RunOptions configured for normal CLI execution.