fix: resolve all nlreturn linter errors

Add blank lines before return statements in all files to satisfy
the nlreturn linter. This improves code readability by providing
visual separation before return statements.

Changes made across 24 files:
- internal/cli/*.go
- internal/secret/*.go
- internal/vault/*.go
- pkg/agehd/agehd.go
- pkg/bip85/bip85.go

All 143 nlreturn issues have been resolved.

internal/secret/helpers.go

@@ -48,6 +48,7 @@ func DetermineStateDir(customConfigDir string) string {
 	if err != nil {
 		// Fallback to a reasonable default if we can't determine user config dir
 		homeDir, _ := os.UserHomeDir()
+
 		return filepath.Join(homeDir, ".config", AppID)
 	}