fix: remove num_ctx parameter from Ollama chat options

The num_ctx parameter was being passed to the Ollama chat API but is no longer needed. This removes it from the options object to simplify the configuration.

Author: roomote

src/api/providers/native-ollama.ts

@@ -190,7 +190,6 @@ export class NativeOllamaHandler extends BaseProvider implements SingleCompletio
 				messages: ollamaMessages,
 				stream: true,
 				options: {
-					num_ctx: modelInfo.contextWindow,
 					temperature: this.options.modelTemperature ?? (useR1Format ? DEEP_SEEK_DEFAULT_TEMPERATURE : 0),
 				},
 			})