Fix cronjob/telegram fallback for keyless server-key providers

Cronjobs and Telegram bots threw a hard error when an agent had no
assigned user API key, even for providers (nvidia/gemini/minimax/
pollinations) whose server-side key ChatEndpoint resolves automatically
via ResolveProviderConfig. The guard blocked every non-empty provider
instead of only "openai", so e.g. the nvidia agent failed on "Jetzt
ausführen" although the normal chat worked.

Mirror ChatEndpoint's three-way handling at all three sites
(ExecuteCronjob, SendCronjobNotification, TelegramService.HandleMessage):
- Anthropic (empty provider): Claude CLI fallback when permitted/available
- "openai": hard error (no server key, no CLI equivalent)
- other providers: pass through with empty token; server key resolved later

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

Services/CronjobService.cs

@@ -91,9 +91,37 @@ public class CronjobService : BackgroundService
 
         // API-Key des Cronjob-Owners für diesen Agent auflösen
         var userApiKey = await _db.GetAgentApiKeyRecord(job.UserId, ctx.AgentId);
+        bool useCliFallback = false;
+
         if (userApiKey == null)
-            throw new Exception($"Kein API-Key für Agent {ctx.AgentId} zugewiesen (User {job.UserId})");
-        ctx.ApiToken = userApiKey.ApiKey;
+        {
+            // Kein User-Key – Verhalten exakt wie ChatEndpoint:
+            //  - Anthropic (Provider leer)        → Claude-CLI-Fallback (sofern berechtigt/verfügbar)
+            //  - "openai"                         → harter Fehler (kein Server-Key, kein CLI-Äquivalent)
+            //  - nvidia/gemini/minimax/pollinations → durchlassen: ResolveProviderConfig löst den Server-Key auf
+            if (string.IsNullOrEmpty(ctx.Provider))
+            {
+                var jobOwner = await _db.GetUser(job.UserId);
+                if (jobOwner != null && !jobOwner.CanUseCli && !jobOwner.IsAdmin)
+                    throw new Exception($"Kein API-Key für Agent {ctx.AgentId} zugewiesen und User {job.UserId} hat keine CLI-Berechtigung.");
+
+                if (!_anthropicService.IsCliAvailable)
+                    throw new Exception($"Kein API-Key für Agent {ctx.AgentId} zugewiesen und Claude CLI nicht verfügbar.");
+
+                useCliFallback = true;
+                _logger.LogInformation("Cronjob '{Name}': Kein API-Key für Agent {AgentId}, verwende CLI-Fallback", job.Name, ctx.AgentId);
+            }
+            else if (ctx.Provider == "openai")
+            {
+                throw new Exception($"Kein API-Key für Agent {ctx.AgentId} zugewiesen (User {job.UserId}). OpenAI benötigt zwingend einen zugewiesenen API-Key.");
+            }
+            // sonst: nvidia/gemini/minimax/pollinations → ctx.ApiToken bleibt leer,
+            // der Server-seitige Provider-Key wird in ResolveProviderConfig aufgelöst.
+        }
+        else
+        {
+            ctx.ApiToken = userApiKey.ApiKey;
+        }
 
         // History aus DB laden. includeThinking=true für OpenAI-kompatible Provider →
         // <think>...</think>-Prefix wird dem Assistant-Text vorangestellt.
@@ -117,6 +145,8 @@ public class CronjobService : BackgroundService
         string responseText;
         if (!string.IsNullOrEmpty(ctx.Provider))
             responseText = await _openAiService.ChatNonStreaming(ctx, history);
+        else if (useCliFallback)
+            responseText = await _anthropicService.ChatNonStreamingViaCli(ctx, history);
         else
             responseText = await _anthropicService.ChatNonStreaming(ctx, history);
 
@@ -150,12 +180,36 @@ public class CronjobService : BackgroundService
 
             // API-Key des Cronjob-Owners für Notify-Agent auflösen
             var notifyApiKey = await _db.GetAgentApiKeyRecord(job.UserId, notifyCtx.AgentId);
+            bool notifyUseCliFallback = false;
+
             if (notifyApiKey == null)
             {
-                _logger.LogWarning("Kein API-Key für Agent {AgentId} (Cronjob '{Name}' Notification)", notifyCtx.AgentId, job.Name);
-                return;
+                // Kein User-Key – Verhalten wie ExecuteCronjob/ChatEndpoint:
+                //  - Anthropic (Provider leer)          → Claude-CLI-Fallback (sofern berechtigt/verfügbar)
+                //  - "openai"                           → abbrechen (kein Server-Key, kein CLI-Äquivalent)
+                //  - nvidia/gemini/minimax/pollinations → durchlassen: Server-Key via ResolveProviderConfig
+                if (string.IsNullOrEmpty(notifyCtx.Provider))
+                {
+                    var notifyOwner = await _db.GetUser(job.UserId);
+                    if ((notifyOwner != null && !notifyOwner.CanUseCli && !notifyOwner.IsAdmin) || !_anthropicService.IsCliAvailable)
+                    {
+                        _logger.LogWarning("Kein API-Key für Agent {AgentId} (Cronjob '{Name}' Notification) und CLI nicht verfügbar/berechtigt", notifyCtx.AgentId, job.Name);
+                        return;
+                    }
+
+                    notifyUseCliFallback = true;
+                }
+                else if (notifyCtx.Provider == "openai")
+                {
+                    _logger.LogWarning("Kein API-Key für Agent {AgentId} (Cronjob '{Name}' Notification, OpenAI benötigt zwingend einen Key)", notifyCtx.AgentId, job.Name);
+                    return;
+                }
+                // sonst: nvidia/gemini/minimax/pollinations → notifyCtx.ApiToken bleibt leer (Server-Key-Auflösung).
+            }
+            else
+            {
+                notifyCtx.ApiToken = notifyApiKey.ApiKey;
             }
-            notifyCtx.ApiToken = notifyApiKey.ApiKey;
 
             // Kurze Zusammenfassung als User-Nachricht in die Notify-Session schreiben
             var summary = $"[Cronjob \"{job.Name}\" wurde in Session \"{job.SessionName}\" ausgeführt]\n\nAntwort:\n{Truncate(responseText, 2000)}";
@@ -183,6 +237,8 @@ public class CronjobService : BackgroundService
             string notifyResponse;
             if (!string.IsNullOrEmpty(notifyCtx.Provider))
                 notifyResponse = await _openAiService.ChatNonStreaming(notifyCtx, notifyHistory);
+            else if (notifyUseCliFallback)
+                notifyResponse = await _anthropicService.ChatNonStreamingViaCli(notifyCtx, notifyHistory);
             else
                 notifyResponse = await _anthropicService.ChatNonStreaming(notifyCtx, notifyHistory);