feat(parser): add AppSyncResolver model

[VatsalGoel3]

Issue number: #6111

Summary

Changes

This PR introduces a new built-in model AppSyncResolverEventModel for the Parser utility in Powertools for AWS Lambda (Python), enabling structured parsing and validation of AWS AppSync Resolver events using Pydantic. The schema supports fields such as arguments, identity, source, request, info, prev, and stash, covering all standard AppSync resolver context attributes.

Additionally:

• A set of identity sub-models (IAM, Cognito, OIDC, Lambda) was introduced.
• New tests for valid and invalid payloads have been added.
• Documentation was updated to reflect the new model in the built-in schema list.
• The model was added to the package exports for use via aws_lambda_powertools.utilities.parser.models.

User experience

Before:
Users had to manually define models for AppSync Resolver events or rely on loosely-typed parsing.

After:
Users can now simply use the built-in AppSyncResolverEventModel to validate and parse incoming AppSync event payloads with full type safety and field coverage using Pydantic.

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Checklist

If your change doesn't seem to apply, please leave them unchecked.

• Meet tenets criteria
• I have performed a self-review of this change
• Changes have been tested
• Changes are documented
• PR title follows conventional commit semantics

Is this a breaking change?

RFC issue number: N/A

Checklist:

• Migration process documented
• Implement warnings (if it can live side by side)

Acknowledgment

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

Disclaimer: We value your time and bandwidth. As such, any pull requests created on non-triaged issues might not be successful.

[boring-cyborg]

Thanks a lot for your first contribution! Please check out our contributing guidelines and don't hesitate to ask whatever you need.
In the meantime, check out the #python channel on our Powertools for AWS Lambda Discord: Invite link

[VatsalGoel3]

@leandrodamascena, I have completed the issue #6111 in this PR, I have followed the guidelines of code completly to the best of my knowledge, as this was my first PR for the Powertools in Python, if anything is missing or needs changes please let me know.
Thank you

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.33%. Comparing base (5aa107c) to head (3c4a83a).
Report is 1 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #6400      +/-   ##
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+ Coverage    96.31%   96.33%   +0.01%     
===========================================
  Files          242      243       +1     
  Lines        11711    11758      +47     
  Branches       871      871              
===========================================
+ Hits         11280    11327      +47     
  Misses         337      337              
  Partials        94       94              

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[leandrodamascena]

Hey @VatsalGoel3! Thanks a lot for this PR! I just left a small comment and after that we are ready to merge.

[leandrodamascena]

Hey @VatsalGoel3! Just a little small change and it's ready to merge.

[VatsalGoel3]

@leandrodamascena, I made the changes

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[leandrodamascena]

Thank you so much for working on this and resolving all the issues in this PR @VatsalGoel3!

Another super cool contribution to Powertools! Approved

[boring-cyborg]

Awesome work, congrats on your first merged pull request and thank you for helping improve everyone's experience!