Fix/collapsed toolbar rename

[sukritgoyal]

Fix: "Rename Folder" now works in Collapsed Toolbar layout

Closes #14082

Problem

When the sidebar is in Collapsed Toolbar mode (compact icon-only view), right-clicking a tab folder and selecting "Rename Folder" did nothing. The option was visible in the context menu but completely unresponsive.

The root cause was an early-return guard in nsZenFolder.rename():

rename() {
  if (!document.documentElement.hasAttribute("zen-sidebar-expanded")) {
    return; // silently bailed out in collapsed mode
  }
  ...
}

In collapsed mode the sidebar has no visible label input, so the inline rename flow (gZenVerticalTabsManager.renameTabStart) can't work — but instead of falling back gracefully, it just returned without any feedback to the user.

Solution

When the sidebar is collapsed, fall back to a native Services.prompt.prompt() dialog pre-filled with the folder's current name. On confirmation, the result is passed to the existing labelElement.onRenameFinished() callback, which handles saving and firing the ZenFolderRenamed event — so all downstream persistence logic is unchanged.

When the sidebar is expanded, the existing inline rename flow is used as before.

Changes

• src/zen/folders/ZenFolder.mjs — Modified rename() to show a prompt dialog instead of silently returning when zen-sidebar-expanded is absent.
• locales/en-US/browser/browser/zen-folders.ftl — Added zen-folder-rename-prompt Fluent string for the prompt message.

Before / After

Sidebar mode	Before	After
Expanded (Single/Multiple toolbar)	✅ Inline rename works	✅ Unchanged
Collapsed Toolbar	❌ Silent no-op	✅ Native prompt dialog

[mr-cheffy]

I think we should move this prompt functionality into renameTabStart so it also works for renaming spaces, tabs, etc.

[mr-cheffy]

Sync value fetching doesn't work in this context. Have you tested this?

Also, why use gBrowser.ownerDocument instead of the document object?

[sukritgoyal]

Actually I am new to open source contributions. If you can guide me how do I test and anything which I need to know other than just coding and development. The codebase is very large.

[mr-cheffy]

Did you get it to build?

[sukritgoyal]

Nope this is the first time I working on open source contributions.

[sukritgoyal]

@mr-cheffy If you can guide me here, I will be really grateful to you!

[ashvwinn]

@sukritgoyal You can read this for guidance https://docs.zen-browser.app/contribute/desktop