Add plan comments

[Florian-Cullmann]

Summary

• add an optional plan-comment prop to the reusable Plan component
• add a Comments field to the demo app and preserve comments through save, import, export, edit, and reopen flows
• display comments in a dedicated Comment tab, independently from the SQL query
• document the public prop and cover the workflow with browser tests

Why

PEV2 only carried the plan source and SQL query through its component and demo data flows, so users had no dedicated place to keep context such as configuration differences or tuning notes. Comments are now stored separately from SQL and shown in their own tab with their original line breaks.

Impact

Existing integrations and previously saved plans remain compatible because the new component prop and stored comment value are optional.

Closes #720

[pgiraud]

@Florian-Cullmann could you please take the comments made in #720 into account?

[Florian-Cullmann]

@pgiraud on it!

[Florian-Cullmann]

@pgiraud done

[pgiraud]

If it doesn't bother you to make a small change, I'd be in favor of not adding the Comment tab when it's empty instead of just disabling it. It's probably just a matter of taste.

While you're at it, can you please, in an additional commit, move the Plan Name for field to the top, before the Plan one?

[Florian-Cullmann]

@pgiraud done

[pgiraud]

Can you please make it so the sample plans selector is on the same line as Plan Name label?

Also, can you please squash the 3 first commits and create one single "Add plan comments" commit?

[pgiraud]

Do you think you'll be able to work on this soon? I'd like to publish a new release.

[Florian-Cullmann]

@pgiraud Done - I moved the sample plans selector next to the Plan Name label and squashed the first three commits. Does this look good to you?

[pgiraud]

Thanks a lot for your contribution to the project.