feat: add support for USE_STRUCTURED_RESPONSE

[suwhang-cisco]

Add a new support for USE_STRUCTURED_RESPONSE where LLM uses structured response tool call as its final output. This flag is false by default (agent instructed to use [Final Answer] stamps instead. When enabled, agent will always do a tool call at the end for the final output.

Description

Please provide a meaningful description of what this change will do, or is for.
Bonus points for including links to related issues, other PRs, or technical
references.

Note that by not including a description, you are asking reviewers to do extra
work to understand the context of this change, which may lead to your PR taking
much longer to review, or result in it not being reviewed at all.

Please ensure commits conform to the Commit Guideline

Type of Change

• Bugfix
• New Feature
• Breaking Change
• Refactor
• Documentation
• Other (please describe)

Pre-release Helm Charts (Optional)

For chart changes, you can test pre-release versions before merging:

• Base repo contributors: Create a branch starting with pre/ for automatic pre-release builds
• Fork contributors: Ask a maintainer to add the helm-prerelease label
• Pre-release charts are published to ghcr.io/cnoe-io/pre-release-helm-charts
• Cleanup happens automatically when the PR closes or label is removed

Checklist

• I have read the contributing guidelines
• Existing issues have been referenced (where applicable)
• I have verified this change is not present in other open pull requests
• Functionality is documented
• All code style checks pass
• New code contribution is covered by automated tests
• All new and existing tests pass

[github-actions]

📊 Test Coverage Report

Main Tests Coverage

Metric	Coverage	Details
Lines	47.1%	4127/8769 lines
Branches	0.0%	0/0 branches

📁 Coverage Artifacts

• Main tests: coverage-reports-main artifact
• RAG tests: coverage-reports-rag artifact (not available)
• Download artifacts to view detailed HTML coverage reports

[github-actions]

📊 Test Coverage Report

Main Tests Coverage

Metric	Coverage	Details
Lines	47.1%	4127/8769 lines
Branches	0.0%	0/0 branches

📁 Coverage Artifacts

• Main tests: coverage-reports-main artifact
• RAG tests: coverage-reports-rag artifact (not available)
• Download artifacts to view detailed HTML coverage reports

[github-actions]

📊 Test Coverage Report

Main Tests Coverage

Metric	Coverage	Details
Lines	47.1%	4127/8770 lines
Branches	0.0%	0/0 branches

📁 Coverage Artifacts

• Main tests: coverage-reports-main artifact
• RAG tests: coverage-reports-rag artifact (not available)
• Download artifacts to view detailed HTML coverage reports

[subbaksh]

You must resync your branch with main before this PR can be merged.

Steps

1. Fetch the latest changes:

   git fetch origin

2. Rebase your branch onto main:

   git checkout <your-branch>
   git rebase origin/main

3. Force push your rebased branch:

   git push --force-with-lease

Important

• Do NOT merge without rebasing first
• Do NOT push without rebasing first

[suwhang-cisco]

new PR #799