fix: implement IsCallbacksEnabled and GetType for cancelableChatModel

[hi-pender]

Summary

This PR adds two interface methods to cancelableChatModel to properly propagate callback and type information from the wrapped inner model.

Changes

• Add IsCallbacksEnabled() bool method to delegate callback status check to the inner model
• Add GetType() string method to return the type name of the inner model

Why

The cancelableChatModel wraps a model.ChatModel to add cancellation support. However, without these methods, the wrapper would lose the ability to report:

1. Whether callbacks are enabled on the underlying model
2. The actual type name of the inner model for logging/debugging purposes

This ensures proper functionality when using the cancelable wrapper with the component callback system and type introspection.

Testing

The implementation delegates to existing utility functions (components.IsCallbacksEnabled, components.GetType, generic.ParseTypeName) which are already tested.

[codecov]

Codecov Report

❌ Patch coverage is 83.33333% with 1 line in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (feat/agent_turn_loop@a4e13f5). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
adk/cancel_wrapper.go	83.33%	1 Missing ⚠️

Additional details and impacted files

@@                   Coverage Diff                   @@
##             feat/agent_turn_loop     #826   +/-   ##
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  Coverage                        ?   79.53%           
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  Files                           ?      148           
  Lines                           ?    16425           
  Branches                        ?        0           
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  Hits                            ?    13064           
  Misses                          ?     2386           
  Partials                        ?      975           

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