feat(hooks): Mark ModelCall and ToolCall events as non-experimental

[zastrowm]

Description

Addresses #667 - we haven't seen any huge deficiencies in these and we need to stabilize hooks

As part of this change we renamed the events to clarify naming and reduce verbosity:

• BeforeToolInvocationEvent -> BeforeToolCallEvent
• AfterToolInvocationEvent -> AfterToolCallEvent
• BeforeModelInvocationEvent -> BeforeModelCallEvent
• AfterModelInvocationEvent -> AfterModelCallEvent

Part of the motivation of the rename is to avoid confusion with BeforeInvocationEvent and BeforeToolInvocation & BeforeModelInvocationEvent, as we've seen folks confusing them quite a bit.

API Bar Raise

The new names need to be API bar-raised.

The existing events that are not changing are as follows:

Event	Purpose
AgentInitializedEvent	Triggered when an agent has been constructed and finished initialization at the end of Agent.__init__.
BeforeInvocationEvent	Triggered at the beginning of a new agent request (__call__, stream_async, or structured_output)
AfterInvocationEvent	Triggered at the end of an agent request, regardless of success or failure. Uses reverse callback ordering
MessageAddedEvent	Triggered when a message is added to the agent's conversation history

The proposed events that are being renamed:

Event	Purpose
BeforeModelInvocationEvent BeforeModelCallEvent	Triggered before the model is invoked for inference
AfterModelInvocationEvent AfterModelCallEvent	Triggered after model invocation completes. Uses reverse callback ordering
BeforeToolInvocationEvent BeforeToolCallEvent	Triggered before a tool is invoked.
AfterToolInvocationEvent AfterToolCallEvent	Triggered after tool invocation completes. Uses reverse callback ordering

Backwards compatibility

• These changes are backwards compatible as the experimental events still exist using aliases
  • We can preserve these for a release or two and then remove the experimental events

Related Issues

#667

Documentation PR

TBD

Type of Change

New feature

Testing

How have you tested the change? Verify that the changes do not break functionality or introduce warnings in consuming repositories: agents-docs, agents-tools, agents-cli

• I ran hatch run prepare

Checklist

• I have read the CONTRIBUTING document
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have added an appropriate example to the documentation to outline the feature, or no new docs are needed
• My changes generate no new warnings
• Any dependent changes have been merged and published

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