fix(ui): properly translate folder view labels and buttons

[jhb-dev]

What?

Fixes several broken translations in the folder view UI:

• Popup group headers "Sort by" / "Order" rendered in English regardless of locale.
• Grid section headers "Folders" / "Documents" rendered in English.
• Folder-row actions menu showed "Folder bearbeiten" (English noun, German verb) instead of "Ordner bearbeiten".
• Move-to-folder drawer showed "Folder hinzufügen" / "Erstellen folder" instead of proper German.
• Collection-folder list selection button used the semantically wrong German "Alles leeren" (meaning "empty everything") for a deselect-all action.

Why?

The folder collection config used hardcoded English labels ({ plural: 'Folders', singular: 'Folder' }) that flowed into several UI labels via getTranslation(), which returns the string as-is for non-translatable values.

Multiple call sites also built button labels via string concatenation (\${t('general:create')} \${label.toLowerCase()}), which produces incorrect output in non-English locales where:

• Word order differs (German: noun then verb — "Ordner erstellen", not "Erstellen ordner").
• Nouns must remain capitalized (German).

Finally, general:clearAll was only used as a "deselect all" button and was literally translated as "Clear all" / "Alles leeren" in most locales, which is misleading.

How?

• Folder collection config (createFolderCollection.ts, buildFolderField.ts): switch labels to translation functions (({ t }) => t('folder:folder') / t('folder:folders')).
• SortByPill: use t('general:sortBy') / t('general:order').
• ItemCardGrid call sites in BrowseByFolder and getFolderResultsComponentAndData: pass translated titles using existing folder:folders / general:documents keys.
• Replace all four \${create} \${label.toLowerCase()} patterns with t('general:createNewLabel', { label }) so word order and casing are decided by each locale's translation string.
• Add new folder:folder and general:sortBy translation keys. Regenerate for all 43 non-English locales.
• Rename general:clearAll → general:deselectAll (semantically correct, not used anywhere else). Regenerate translations.