add setting to set close button label

[MarieComet]

#12

---

Note

Low Risk
Low risk: adds an optional block attribute and editor control to override close button text, with straightforward serialization changes and updated translation files.

Overview
Adds a new closeButtonLabel block attribute and an inspector TextControl so editors can override the modal close button text when the close button is enabled.

Updates both editor preview and saved markup to render the custom label (falling back to the default Close this dialog window string), and refreshes i18n catalogs (.pot, fr_FR files) plus bumps package/version metadata to 1.0.6.

^{Reviewed by Cursor Bugbot for commit 43dc970. Bugbot is set up for automated code reviews on this repo. Configure here.}

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

^{Reviewed by Cursor Bugbot for commit 8248c8b. Configure here.}