Highlight ROS Lyrical changes with examples (backport #6765)

[mergify]

Description

This PR highlights new features in ROS Lyrical. I tried to include a reason for using the feature and an example.

I vibe coded a script to diff Kilted and Lyrical, manually curated a list of interesting changes in google sheets, organized them in an outline in a google doc, and then wrote up nice descriptions for each of them. This took a bit of time, but I enjoyed learning and trying out everything new in Lyrical.

I deleted some of the existing changelog entries that subjectively I didn't think I could write a good example for. I'm relying on the full Lyrical changelog to fill the gaps.

Did you use Generative AI?

Yeah. I used a lot of gemini for proof reading and minimizing examples. I ran everything myself to make sure the code is correct though.

Additional Information

I haven't tried rendering the docs at all. Hope it works 🤞

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This is an automatic backport of pull request #6765 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 5c6892f has failed:

On branch mergify/bp/humble/pr-6765
Your branch is up to date with 'origin/humble'.

You are currently cherry-picking commit 5c6892f1.
  (fix conflicts and run "git cherry-pick --continue")
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Changes to be committed:
	new file:   source/Releases/images/ros2_topic_bw_all.gif

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   source/Releases/Release-Lyrical-Luth.rst

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[github-actions]

HTML artifacts: https://github.com/ros2/ros2_documentation/actions/runs/25925942161/artifacts/7020528829.

To view the resulting site:

1. Click on the above link to download the artifacts archive
2. Extract it
3. Open html-artifacts-6780/index.html in your favorite browser