move tool caller definition out of agent module

[pgrayy]

Description

Moving ToolCaller out of the Agent class and into a dedicated module. This will allow us to more easily support direct tool calling in the upcoming BidiAgent.

Note, this is setup as a backwards compatible change.

Related Issues

Documentation PR

Internal only change.

Type of Change

Other (please describe): Internal code reorganization.

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: Relying on existing unit tests.

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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[codecov]

Codecov Report

❌ Patch coverage is 95.83333% with 3 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/strands/tools/_caller.py	95.52%	1 Missing and 2 partials ⚠️

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