Initial open-source release (MIT): image2api AI gateway

Full Go backend + Vue 3 frontend, OpenAI-compatible API, multi-provider
account pools, billing/admin, Docker one-command deploy with auto HTTPS.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/internal/service/password.go

@@ -0,0 +1,46 @@
+package service
+
+import (
+	"crypto/sha256"
+	"crypto/subtle"
+	"encoding/base64"
+	"encoding/hex"
+	"strings"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+func GeneratePasswordHash(password string) (string, error) {
+	hash, err := bcrypt.GenerateFromPassword(bcryptPrehash(password), 12)
+	if err != nil {
+		return "", err
+	}
+	return string(hash), nil
+}
+
+func VerifyPassword(password, stored string) bool {
+	stored = strings.TrimSpace(stored)
+	if stored == "" {
+		return false
+	}
+
+	if strings.HasPrefix(stored, "bcrypt$") {
+		hash := stored[len("bcrypt$"):]
+		return bcrypt.CompareHashAndPassword([]byte(hash), bcryptPrehash(password)) == nil
+	}
+
+	parts := strings.SplitN(stored, "$", 3)
+	if len(parts) != 3 || parts[0] != "sha256" {
+		return false
+	}
+	expected := sha256.Sum256([]byte(parts[1] + password))
+	expectedHex := hex.EncodeToString(expected[:])
+	return subtle.ConstantTimeCompare([]byte(expectedHex), []byte(parts[2])) == 1
+}
+
+func bcryptPrehash(password string) []byte {
+	sum := sha256.Sum256([]byte(password))
+	dst := make([]byte, base64.StdEncoding.EncodedLen(len(sum)))
+	base64.StdEncoding.Encode(dst, sum[:])
+	return dst
+}