chore(examples): bump tools_runner.py to claude-sonnet-4-5-20250929

[GopalGB]

What

Bump the model in examples/tools_runner.py from claude-3-5-sonnet-latest to claude-sonnet-4-5-20250929.

Why

examples/tools_runner.py is the only example file still pointing at claude-3-5-sonnet-latest. Every sibling example uses claude-sonnet-4-5-20250929:

$ grep -h 'model=' examples/*.py | sort -u
        model="anthropic.claude-sonnet-4-5-20250929-v1:0",
        model="claude-haiku-4-5",
        model="claude-sonnet-4-5",
        model="claude-sonnet-4-5-20250929",
        model="claude-sonnet-4-6",
        model="claude-3-5-sonnet-latest",   <- the outlier

Aligning this example so copy-paste users land on a current model.

Notes

• Per CONTRIBUTING.md, examples/ is not modified by the generator, so this edit is safe to land manually.
• The example logic is unchanged — only the model identifier moves to the current default seen elsewhere in examples/.

How to test

$ ANTHROPIC_API_KEY=... uv run python examples/tools_runner.py

Output should match the previous behavior — the runner queries the weather tool and prints messages.

[GopalGB]

Trivial example bump from claude-opus-4-1-20250805 to claude-sonnet-4-5-20250929 to match current default sonnet. CLA signed. Happy to close if you'd prefer a different model — just let me know.

[karpetrosyan]

Thanks for the PR!