Fix local LLM prompt truncation and context window limit guard

.app.pid

@@ -1 +1 @@
-97312
+98070

server.ts

@@ -92,10 +92,15 @@ const generateTextWithLLMFallback = async (
   const modelName = llmConfig?.lmStudioModel || "local-model";
   const apiKey = llmConfig?.customApiKey;
 
-  // 1. Direct LM Studio / Local LLM request
-  if (primary === 'lmstudio' || primary === 'openai_compatible') {
+  // Safely limit prompt length for local LLMs (max ~12,000 chars ~ 3000 tokens context limit)
+  const safePrompt = prompt.length > 12000 ? prompt.substring(0, 12000) + "\n\n[Content truncated for context size]" : prompt;
+
+  const hasValidGeminiKey = !!process.env.GEMINI_API_KEY && process.env.GEMINI_API_KEY.trim().length > 10;
+
+  // 1. Direct LM Studio / Local LLM request or Gemini key is missing
+  if (primary === 'lmstudio' || primary === 'openai_compatible' || !hasValidGeminiKey) {
     console.log(`[LLM Router] Routing directly to Local LLM (${baseUrl})...`);
-    const resultText = await callLMStudioCompletion(prompt, "Respond strictly in requested JSON format.", baseUrl, modelName, apiKey);
+    const resultText = await callLMStudioCompletion(safePrompt, "Respond strictly in requested JSON format.", baseUrl, modelName, apiKey);
     return { text: resultText, providerUsed: `Local LLM (${modelName})` };
   }
 
@@ -112,7 +117,7 @@ const generateTextWithLLMFallback = async (
 
     const response = await ai.models.generateContent({
       model: "gemini-3.6-flash",
-      contents: prompt,
+      contents: safePrompt,
       config
     });
 
@@ -127,7 +132,7 @@ const generateTextWithLLMFallback = async (
       console.log(`[LLM Router] Falling back to Local LM Studio endpoint at ${baseUrl}...`);
       try {
         const localResult = await callLMStudioCompletion(
-          `${prompt}\n\nIMPORTANT: Respond with clean JSON matching the requested structure.`,
+          `${safePrompt}\n\nIMPORTANT: Respond with clean JSON matching the requested structure.`,
           "You are a backup AI assistant filling in for Gemini. Return structured JSON.",
           baseUrl,
           modelName,