fix: code review cleanup

- Fixed TypeScript exactOptionalPropertyTypes errors in chat components
- Removed console.error statements (errors are handled via state)
- Fixed type compatibility issues with undefined vs null values
- All chat-related files now pass strict TypeScript checks

apps/web/src/hooks/useChat.ts

@@ -173,9 +173,9 @@ export function useChat(options: UseChatOptions = {}): UseChatReturn {
         const request = {
           model,
           messages: apiMessages,
-          temperature,
-          maxTokens,
-          systemPrompt,
+          ...(temperature !== undefined && { temperature }),
+          ...(maxTokens !== undefined && { maxTokens }),
+          ...(systemPrompt !== undefined && { systemPrompt }),
         };
 
         // Call LLM API
@@ -188,8 +188,8 @@ export function useChat(options: UseChatOptions = {}): UseChatReturn {
           content: response.message.content,
           createdAt: new Date().toISOString(),
           model: response.model,
-          promptTokens: response.promptEvalCount,
-          completionTokens: response.evalCount,
+          promptTokens: response.promptEvalCount ?? 0,
+          completionTokens: response.evalCount ?? 0,
           totalTokens: (response.promptEvalCount ?? 0) + (response.evalCount ?? 0),
         };