fix: extract User/Bot/unknown author type strings as constants

Address goconst lint: extract repeated "User", "Bot", "unknown" strings
into AuthorTypeUser, AuthorTypeBot, AuthorTypeUnknown constants in the
prinfo package.

Signed-off-by: Javier Rodriguez <javier@chainloop.dev>

Author: javirln

internal/prinfo/prinfo.go

@@ -25,6 +25,13 @@ const (
 	EvidenceID = "CHAINLOOP_PR_INFO"
 	// EvidenceSchemaURL is the URL to the JSON schema for PR/MR info
 	EvidenceSchemaURL = "https://schemas.chainloop.dev/prinfo/1.3/pr-info.schema.json"
+
+	// AuthorTypeUser represents a human user account
+	AuthorTypeUser = "User"
+	// AuthorTypeBot represents a bot/service account
+	AuthorTypeBot = "Bot"
+	// AuthorTypeUnknown represents an account with unknown type
+	AuthorTypeUnknown = "unknown"
 )
 
 // Author represents the author of the PR/MR with account type information
@@ -86,7 +93,7 @@ func (d *Data) UnmarshalJSON(b []byte) error {
 	// Fall back to string format
 	var login string
 	if err := json.Unmarshal(aux.Author, &login); err == nil {
-		d.Author = &Author{Login: login, Type: "unknown"}
+		d.Author = &Author{Login: login, Type: AuthorTypeUnknown}
 		return nil
 	}
 

pkg/attestation/crafter/prmetadata.go

@@ -439,9 +439,9 @@ func fetchGitLabMRDetails(ctx context.Context, baseURL, projectPath, mrIID, toke
 
 	// Extract author with bot detection
 	if mrResponse.Author.Username != "" {
-		authorType := "User"
+		authorType := prinfo.AuthorTypeUser
 		if mrResponse.Author.Bot {
-			authorType = "Bot"
+			authorType = prinfo.AuthorTypeBot
 		}
 		details.Author = &prinfo.Author{
 			Login: mrResponse.Author.Username,
@@ -451,9 +451,9 @@ func fetchGitLabMRDetails(ctx context.Context, baseURL, projectPath, mrIID, toke
 
 	// Extract reviewers with bot detection
 	for _, r := range mrResponse.Reviewers {
-		reviewerType := "User"
+		reviewerType := prinfo.AuthorTypeUser
 		if r.Bot {
-			reviewerType = "Bot"
+			reviewerType = prinfo.AuthorTypeBot
 		}
 		details.Reviewers = append(details.Reviewers, prinfo.Reviewer{
 			Login:     r.Username,
@@ -469,9 +469,9 @@ func fetchGitLabMRDetails(ctx context.Context, baseURL, projectPath, mrIID, toke
 // to one of the allowed values: "User", "Bot", or "unknown".
 func normalizeAuthorType(authorType string) string {
 	switch authorType {
-	case "User", "Bot":
+	case prinfo.AuthorTypeUser, prinfo.AuthorTypeBot:
 		return authorType
 	default:
-		return "unknown"
+		return prinfo.AuthorTypeUnknown
 	}
 }