Localization: "Add Locales" starts an irreversible multi-minute operation with no confirmation - one click creates ~900 assets that cannot be cancelled or undone

Steps to reproduce:

1. Create a new project
2. Install the Localization package (com.unity.localization)
3. Open Edit > Project Settings > Localization and click "Create" to make the settings asset
4. Click "Add Locale", then click "Select All"
5. Click "Add Locales" and choose a folder inside the project
6. Observe whether any confirmation or warning is shown before the operation begins
7. While the progress bar runs, look for a Cancel button and press Esc
8. Time the operation and count the assets created
9. When it finishes, press ⌘Z

Actual results: The operation begins immediately with no confirmation and no indication of what it will do. It creates [N] Locale assets and blocks the Editor for [T]. The progress bar has no Cancel button and Esc has no effect, so the only exit is force-quitting Unity. When it completes, ⌘Z does not remove the created assets — they must be deleted by hand.

Two clicks - "Select All" then "Add Locales" - therefore commit the user to an operation that cannot be stopped while it runs, cannot be undone once it finishes, and was never described beforehand.

Expected results: A confirmation dialog before the operation starts, stating how many assets will be created and that the operation cannot be cancelled or undone, with the option to proceed or abort

Reproducible with versions: 1.5.12 (6000.5.7f1, 6000.6.0f1, 6000.7.0a6)

Tested on (OS): MacBook Pro - Tahoe 26.6.2

Notes:

• The request here is a confirmation before starting, not a Cancel button. If the absence of cancel is deliberate - a partial run would leave some locales created and registered and others not, with no rollback - then a confirmation is the necessary counterpart: the user has to commit up front and cannot commit to something they were not told about