Port feature/agent_framework commits to main branch

[dbwiddis]

We want to preserve the original PR commit history

Do NOT "Squash and Merge".  Choose the "Rebase and Merge" option.

Description

Backports all commits from feature/agent_framework branch (except those that are already on main or were CI-specific for the feature branch/2.11 development).

Issues Resolved

Fixes #264

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[opensearch-trigger-bot]

The backport to 2.x failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/flow-framework/backport-2.x 2.x
# Navigate to the new working tree
pushd ../.worktrees/flow-framework/backport-2.x
# Create a new branch
git switch --create backport/backport-297-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 0f23dff293a5b18868b004546ff2613f887f558e
# Push it to GitHub
git push --set-upstream origin backport/backport-297-to-2.x
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/flow-framework/backport-2.x

Then, create a pull request where the base branch is 2.x and the compare/head branch is backport/backport-297-to-2.x.