[6.x] Blueprint button order changes

[jaygeorge]

Description of the Problem

Related to #12093, There's been ongoing discussion about how the button row should behave for blueprints—see the feedback thread for full context.

In short:

• Users expect the primary button to save and close the current stack, so they can move on to the next one.
• The current primary button closes everything—so if you press it without noticing, you lose your place and have to navigate back through all stacks.
• Too many buttons increase cognitive load.

What this PR Does

Simplifies the button row to a maximum of two buttons, with consistent keyboard shortcuts throughout.

Single-level stacks show one button:

• Save—saves and closes the stack.

Multi-level stacks show two buttons:

• Save (primary)—saves and closes the current stack.
• Save All—saves and closes all stacks.

Keyboard shortcuts (available everywhere):

• cmd+s—soft-save, keeping the stack open (consistent with behaviour elsewhere in the control panel).
• cmd+shift+s—save all, closing every open stack. Works on single stacks too.

A tooltip on the Save All button aids discoverability for users who haven't encountered the shortcut yet.

How to Reproduce

1. Open a stack for a field like replicator
2. Add a further field to a set and open that to simulate two stacks

[jasonvarga]

I'm happy to update this myself, but I'm just gonna dump this AI review:

Warning: Missing localization for "Save All"

The new button text __('Save All') has no translation entries in any language file. The old strings it replaces ("Apply & Close All" and "Save & Close All") had translations in at least 5 languages (de, de_CH, fr, nl, ru). Non-English users will see untranslated English text.

Warning: softSave and commitAndSaveTopStack call saveRootForm() for nested fields, but changes haven't propagated to the root form

Both softSave() and commitAndSaveTopStack() pass shouldSaveRoot: true, which triggers saveRootForm() → emits root-form-save → the Builder/fieldset form saves.

For a top-level field this works correctly: the committed event synchronously updates the RegularField → blueprint data before saveRootForm() fires.

For a nested field (e.g. a field inside a replicator set), the committed event only updates the parent Settings' internal values state. The parent Settings hasn't committed back to the blueprint data yet. So saveRootForm() persists the blueprint in its pre-edit state — the nested field's changes won't actually be on disk until the parent stack is also saved.

This isn't data loss (changes stay in memory), but it fires an unnecessary HTTP request and could mislead users into thinking their changes are persisted when they're not. Consider either:

• Removing shouldSaveRoot: true from commitAndSaveTopStack (it only needs to close the current stack), or
• Only setting shouldSaveRoot when !this.isNestedField

Note: commitAndSaveTopStack is functionally identical to commitAndSave

Both methods call this.commit({ shouldSaveRoot: true }) with no other differences. Consider consolidating or having one delegate to the other.

Note: saveAllTooltipText is a trivial wrapper

The computed saveAllTooltipText just returns this.saveAllShortcutLabel with no added logic. Could be inlined directly in the template as v-tooltip="saveAllShortcutLabel".