feat: add implementation of a2a and eino adk extension

[meguminnnnnnnnn]

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[github-actions]

Need to create a new tag

The following modules have changes and may need version updates:

• a2a (Current: a2a/v0.0.1-alpha.1)

⚠️ Please create and push new version tags for these modules after merging this PR.

[github-actions]

Need to create a new tag

The following modules have changes and may need version updates:

• a2a (Current: a2a/v0.0.1-alpha.1)

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[github-actions]

Need to create a new tag

The following modules have changes and may need version updates:

• a2a (Current: a2a/v0.0.1-alpha.2)

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[github-actions]

Need to create a new tag

The following modules have changes and may need version updates:

• a2a (Current: a2a/v0.0.1-alpha.2)

⚠️ Please create and push new version tags for these modules after merging this PR.

[github-actions]

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• a2a (Current: a2a/v0.0.1-alpha.2)

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[github-actions]

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• a2a (Current: a2a/v0.0.1-alpha.3)

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[github-actions]

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• a2a (Current: a2a/v0.0.1-alpha.4)

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