Initial commit of Descrybe v2 without local scratch artifacts.

Drop one-shot tmp/axe scripts and agent i18n scratch so the Gitea tree is deployable.

apps/api/internal/auth/password.go

@@ -0,0 +1,61 @@
+package auth
+
+import (
+	"crypto/rand"
+	"crypto/subtle"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"strings"
+
+	"golang.org/x/crypto/argon2"
+)
+
+const (
+	argonTime    = 1
+	argonMemory  = 64 * 1024
+	argonThreads = 4
+	argonKeyLen  = 32
+	argonSaltLen = 16
+)
+
+func HashPassword(password string) (string, error) {
+	if len(password) < 8 {
+		return "", ErrPasswordTooShort
+	}
+	salt := make([]byte, argonSaltLen)
+	if _, err := rand.Read(salt); err != nil {
+		return "", err
+	}
+	hash := argon2.IDKey([]byte(password), salt, argonTime, argonMemory, argonThreads, argonKeyLen)
+	b64Salt := base64.RawStdEncoding.EncodeToString(salt)
+	b64Hash := base64.RawStdEncoding.EncodeToString(hash)
+	return fmt.Sprintf("$argon2id$v=%d$m=%d,t=%d,p=%d$%s$%s",
+		argon2.Version, argonMemory, argonTime, argonThreads, b64Salt, b64Hash), nil
+}
+
+func VerifyPassword(encoded, password string) (bool, error) {
+	parts := strings.Split(encoded, "$")
+	if len(parts) != 6 || parts[1] != "argon2id" {
+		return false, errors.New("invalid password hash format")
+	}
+	var version int
+	if _, err := fmt.Sscanf(parts[2], "v=%d", &version); err != nil {
+		return false, err
+	}
+	var memory, timeCost uint32
+	var threads uint8
+	if _, err := fmt.Sscanf(parts[3], "m=%d,t=%d,p=%d", &memory, &timeCost, &threads); err != nil {
+		return false, err
+	}
+	salt, err := base64.RawStdEncoding.DecodeString(parts[4])
+	if err != nil {
+		return false, err
+	}
+	want, err := base64.RawStdEncoding.DecodeString(parts[5])
+	if err != nil {
+		return false, err
+	}
+	got := argon2.IDKey([]byte(password), salt, timeCost, memory, threads, uint32(len(want)))
+	return subtle.ConstantTimeCompare(want, got) == 1, nil
+}