frontend-foundation: GOAT front-end Phase 1 — auth, tag management, public tag page (22/22 spec scenarios pass)

frontend/internal/auth/passwords.go

@@ -0,0 +1,18 @@
+// Package auth provides password hashing and session handling for WhereWoof.
+package auth
+
+import "golang.org/x/crypto/bcrypt"
+
+// HashPassword returns a bcrypt hash of the given plaintext password.
+func HashPassword(password string) (string, error) {
+	b, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
+	if err != nil {
+		return "", err
+	}
+	return string(b), nil
+}
+
+// CheckPassword reports whether the plaintext password matches the bcrypt hash.
+func CheckPassword(hash, password string) bool {
+	return bcrypt.CompareHashAndPassword([]byte(hash), []byte(password)) == nil
+}