chore: Remove Agent after Haystack 2.12 release

[julian-risch]

Related Issues

• Related to Move Agent from experimental to main #250

Proposed Changes:

• Remove Agent, State, ToolInvoker, Tool, ComponentTool
• Remove GitHub Issue resolver agent example
• Remove pydocs

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Notes for the reviewer

Checklist

• I have read the contributors guidelines and the code of conduct
• I have updated the related issue with new insights and changes
• I added unit tests and updated the docstrings
• I've used one of the conventional commit types for my PR title: fix:, feat:, build:, chore:, ci:, docs:, style:, refactor:, perf:, test:.
• I documented my code
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Pull Request Test Coverage Report for Build 14243735868

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-3.6%) to 85.127%

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Totals
Change from base Build 14239876064:	-3.6%
Covered Lines:	435
Relevant Lines:	511

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[sjrl]

@julian-risch for the Github components do you think it would be worth making an integration out of them?

[julian-risch]

Ah, yes, that seems like a good option. I was wondering where we could keep them. The alternative of keeping them in experimental or deleting them entirely are not as good.

[julian-risch]

I opened two draft PRs so that we can move forward.
deepset-ai/haystack-core-integrations#1637
deepset-ai/haystack-cookbook#183

[sjrl]

Thanks!