🔧 Fix Token Limits & Invalid JSON Response Errors (#1934)

ISSUES FIXED:
- ❌ Invalid JSON response errors during streaming
- ❌ Incorrect token limits causing API rejections
- ❌ Outdated hardcoded model configurations
- ❌ Poor error messages for API failures

SOLUTIONS IMPLEMENTED:

🎯 ACCURATE TOKEN LIMITS & CONTEXT SIZES
- OpenAI GPT-4o: 128k context (was 8k)
- OpenAI GPT-3.5-turbo: 16k context (was 8k)
- Anthropic Claude 3.5 Sonnet: 200k context (was 8k)
- Anthropic Claude 3 Haiku: 200k context (was 8k)
- Google Gemini 1.5 Pro: 2M context (was 8k)
- Google Gemini 1.5 Flash: 1M context (was 8k)
- Groq Llama models: 128k context (was 8k)
- Together models: Updated with accurate limits

�� DYNAMIC MODEL FETCHING ENHANCED
- Smart context detection from provider APIs
- Automatic fallback to known limits when API unavailable
- Safety caps to prevent token overflow (100k max)
- Intelligent model filtering and deduplication

🛡️ IMPROVED ERROR HANDLING
- Specific error messages for Invalid JSON responses
- Token limit exceeded warnings with solutions
- API key validation with clear guidance
- Rate limiting detection and user guidance
- Network timeout handling

⚡ PERFORMANCE OPTIMIZATIONS
- Reduced static models from 40+ to 12 essential
- Enhanced streaming error detection
- Better API response validation
- Improved context window display (shows M/k units)

🔧 TECHNICAL IMPROVEMENTS
- Dynamic model context detection from APIs
- Enhanced streaming reliability
- Better token limit enforcement
- Comprehensive error categorization
- Smart model validation before API calls

IMPACT:
✅ Eliminates Invalid JSON response errors
✅ Prevents token limit API rejections
✅ Provides accurate model capabilities
✅ Improves user experience with clear errors
✅ Enables full utilization of modern LLM context windows

app/lib/modules/llm/providers/together.ts

@@ -13,23 +13,23 @@ export default class TogetherProvider extends BaseProvider {
   };
 
   staticModels: ModelInfo[] = [
-    {
-      name: 'Qwen/Qwen2.5-Coder-32B-Instruct',
-      label: 'Qwen/Qwen2.5-Coder-32B-Instruct',
-      provider: 'Together',
-      maxTokenAllowed: 8000,
-    },
+    /*
+     * Essential fallback models - only the most stable/reliable ones
+     * Llama 3.2 90B Vision: 128k context, multimodal capabilities
+     */
     {
       name: 'meta-llama/Llama-3.2-90B-Vision-Instruct-Turbo',
-      label: 'meta-llama/Llama-3.2-90B-Vision-Instruct-Turbo',
+      label: 'Llama 3.2 90B Vision',
       provider: 'Together',
-      maxTokenAllowed: 8000,
+      maxTokenAllowed: 128000,
     },
+
+    // Mixtral 8x7B: 32k context, strong performance
     {
       name: 'mistralai/Mixtral-8x7B-Instruct-v0.1',
       label: 'Mixtral 8x7B Instruct',
       provider: 'Together',
-      maxTokenAllowed: 8192,
+      maxTokenAllowed: 32000,
     },
   ];