chore: Add "Willingness to contribute" dropdown to issue templates

[comphead]

Which issue does this PR close?

• No tracking issue, this is a small repository chore.

Rationale for this change

Ports apache/datafusion-comet#6688, which took the idea from the iceberg-rust issue templates. Reporters say up front whether they can contribute the fix or feature, so reviewers don't have to ask in a follow-up comment.

What changes are included in this PR?

Adds an optional "Willingness to contribute" dropdown with three options to bug_report.yml and feature_request.yml. The wording is specific to bug fixes in the bug template and to features in the feature template.

What is the testing strategy for this PR?

Issue templates have no automated tests. Both files parse as YAML and the dropdown has the same shape as in the iceberg-rust and Comet templates.

Are there any user-facing changes?

New issues filed from the bug report and feature request forms get one extra optional dropdown. There are no API changes.

[asolimando]

LGTM, the provided options and the wording used makes sense. I think it will be beneficial to move away from the take mechanism

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.74%. Comparing base (1c43063) to head (2955918).
⚠️ Report is 15 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #26120      +/-   ##
==========================================
+ Coverage   82.73%   82.74%   +0.01%     
==========================================
  Files        1147     1147              
  Lines      449389   449756     +367     
  Branches   449389   449756     +367     
==========================================
+ Hits       371788   372157     +369     
+ Misses      54943    54925      -18     
- Partials    22658    22674      +16     

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[2010YOUY01]

Thank you, I agree this would be helpful.

To other reviewers, you can preview by try opening an issue in comet: https://github.com/apache/datafusion-comet/issues

I also suggest we can mention the contributions should follow AI policy

[2010YOUY01]

I don't quite get this point, does that mean "I'm willing to contribute, but there are something I'm uncertain (described in issue), would open a PR after someone answer it"

[alamb]

Maybe we could use the phrase "plan" instead of "am willing"?

Perhaps something like:

I plan contribute a fix for this bug independently
I would like contribute a fix for this bug, but request guidance from the DataFusion community
I cannot contribute a fix for this bug at this time

[alamb]

LGTM, the provided options and the wording used makes sense. I think it will be beneficial to move away from the take mechanism

Should we also plan to remove the take action (and its documentation)?

[alamb]

See related ticket

• Consider removing the take action / open ticket assignment #26063