docs: update AI module README with latest features

- Add comprehensive documentation for the new Query functionality
- Update interface method names from Call to Plan for consistency
- Add OpenAI GPT-4O model support documentation
- Include detailed usage examples for basic and custom schema queries
- Add configuration examples for multiple model services
- Document new features like ResetHistory, Usage statistics, and automatic type conversion
- Expand advanced features section with custom output format examples
- Update all code examples to reflect the latest API changes

The documentation now reflects the current state of the AI module with all three core capabilities:
- Planning (renamed from Call)
- Assertion
- Query (new feature)

All examples and configurations are updated to match the latest implementation.

mcphost/chat.go

@@ -124,7 +124,7 @@ func (c *Chat) runPrompt(ctx context.Context, prompt string) error {
 	var result *ai.PlanningResult
 	var err error
 	_ = spinner.New().Title("Thinking...").Action(func() {
-		result, err = c.planner.Call(ctx, planningOpts)
+		result, err = c.planner.Plan(ctx, planningOpts)
 	}).Run()
 	if err != nil {
 		return err