feat: Stripe-Key-Checker, Krea AI Pattern, Scan-Progress-Tracking

- StripeKeyChecker: 2-Schritt-Check (/v1/balance + /v1/account), Live/Test-Erkennung, Balance, Account-Details
- KeyPatterns: Stripe-Patterns einkommentiert (sk_live_, sk_test_), Krea AI Pattern (UUID:Token), Mindest-Suchlänge 4
- KeyScannerService: Stripe-Check integriert, Auto-Check nach Scan entfernt (manuell separat), Progress-Tracking (Phase, Detail, Current/Total, KeysFound)
- ApiKeysEndpoint: Stripe in HandleCheck/HandleCheckAll/HandleAdopt, Progress im Status-Endpoint
- Frontend: Live-Fortschrittsanzeige mit Spinner, Phase, Query, Counter, Polling 1.5s, Krea AI in typeNames/typeIcons

Services/KeyPatterns.cs

@@ -19,6 +19,9 @@ public static class KeyPatterns
         (@"sk-ant-oat01-[A-Za-z0-9_\-]{95}", "sk-ant-oat01", "anthropic_oauth"),
         (@"sk-ant-api03-[A-Za-z0-9_\-]{95}", "sk-ant-api03", "anthropic_api"),
 
+        // Krea AI (UUID:Base32Token)
+        (@"[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}:[A-Za-z0-9]{32}", "krea", "krea_ai"),
+
         // OpenAI
         (@"sk-proj-[A-Za-z0-9_\-]{80,200}", "sk-proj-", "openai_project"),
         (@"sk-svcacct-[A-Za-z0-9_\-]{80,200}", "sk-svcacct-", "openai_service"),
@@ -56,7 +59,7 @@ public static class KeyPatterns
     /// Filtert zu generische Suchterme aus (z.B. "sk-", "SG.", "SK").
     /// </summary>
     public static readonly (string Pattern, string SearchTerm, string Type)[] ForCodeSearch =
-        All.Where(p => p.SearchTerm.Length >= 5).ToArray();
+        All.Where(p => p.SearchTerm.Length >= 4).ToArray();
 
     // ── Kompilierte Regexe (einmalig, alle Patterns) ──
 
@@ -84,6 +87,9 @@ public static class KeyPatterns
         if (key.StartsWith("hf_", StringComparison.Ordinal)) return "huggingface";
         if (key.StartsWith("SG.", StringComparison.Ordinal)) return "sendgrid";
         if (key.StartsWith("xoxb-", StringComparison.Ordinal)) return "slack";
+        // Krea AI: UUID:Token Format
+        if (key.Length == 69 && key[8] == '-' && key[13] == '-' && key[18] == '-' && key[23] == '-' && key[36] == ':')
+            return "krea_ai";
         return "unknown";
     }
 
@@ -114,6 +120,7 @@ public static class KeyPatterns
             "stripe_test" => "Stripe Test",
             "sendgrid" => "SendGrid",
             "slack" => "Slack",
+            "krea_ai" => "Krea AI",
             _ => type
         };
     }