feat: add Gemini 2.0 Flash-thinking-exp-01-21 model with 65k token support (#1202)

Added the new gemini-2.0-flash-thinking-exp-01-21 model to the GoogleProvider's static model configuration. This model supports a significantly increased maxTokenAllowed limit of 65,536 tokens, enabling it to handle larger context windows compared to existing Gemini models (previously capped at 8k tokens). The model is labeled as "Gemini 2.0 Flash-thinking-exp-01-21" for clear identification in the UI/dropdowns.

Author: saif78642

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

@@ -14,6 +14,7 @@ export default class GoogleProvider extends BaseProvider {
 
   staticModels: ModelInfo[] = [
     { name: 'gemini-1.5-flash-latest', label: 'Gemini 1.5 Flash', provider: 'Google', maxTokenAllowed: 8192 },
+    { name: 'gemini-2.0-flash-thinking-exp-01-21', label: 'Gemini 2.0 Flash-thinking-exp-01-21', provider: 'Google', maxTokenAllowed: 65536 },
     { name: 'gemini-2.0-flash-exp', label: 'Gemini 2.0 Flash', provider: 'Google', maxTokenAllowed: 8192 },
     { name: 'gemini-1.5-flash-002', label: 'Gemini 1.5 Flash-002', provider: 'Google', maxTokenAllowed: 8192 },
     { name: 'gemini-1.5-flash-8b', label: 'Gemini 1.5 Flash-8b', provider: 'Google', maxTokenAllowed: 8192 },