legacy UI (#4612)

# Description of Changes

<!--
Please provide a summary of the changes, including:

- What was changed
- Why the change was made
- Any challenges encountered

Closes #(issue_number)
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---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.

---------

Co-authored-by: Claude <[email protected]>
Co-authored-by: EthanHealy01 <[email protected]>
Co-authored-by: EthanHealy01 <[email protected]>

app/core/src/main/resources/messages_en_GB.properties

@@ -1946,6 +1946,25 @@ viewer.zoomIn=Zoom in
 # Tool Picker
 toolPicker.searchPlaceholder=Search tools...
 toolPicker.noToolsFound=No tools found
+toolPanel.toggle.legacy=Switch to legacy mode
+toolPanel.toggle.sidebar=Switch to sidebar mode
+toolPanel.placeholder=Choose a tool to get started
+toolPanel.legacy.heading=All tools (legacy view)
+toolPanel.legacy.tagline=Browse and launch tools while keeping the classic full-width gallery.
+toolPanel.legacy.descriptionsOn=Showing descriptions
+toolPanel.legacy.descriptionsOff=Descriptions hidden
+toolPanel.legacy.noResults=Try adjusting your search or toggle descriptions to find what you need.
+toolPanel.legacy.matchedSynonym=Matches "{{text}}"
+toolPanel.modePrompt.title=Choose how you browse tools
+toolPanel.modePrompt.description=Preview both layouts and decide how you want to explore Stirling PDF tools.
+toolPanel.modePrompt.sidebarTitle=Advanced sidebar
+toolPanel.modePrompt.sidebarDescription=Keep tools alongside your workspace for quick switching.
+toolPanel.modePrompt.recommended=Recommended
+toolPanel.modePrompt.chooseSidebar=Use advanced sidebar
+toolPanel.modePrompt.legacyTitle=Legacy fullscreen
+toolPanel.modePrompt.legacyDescription=Browse every tool in a catalogue that covers the workspace until you pick one.
+toolPanel.modePrompt.chooseLegacy=Use legacy fullscreen
+toolPanel.modePrompt.dismiss=Maybe later
 pageEditor.reset=Reset Changes
 pageEditor.zoomIn=Zoom In
 pageEditor.zoomOut=Zoom Out
@@ -1958,3 +1977,39 @@ viewer.nextPage=Next Page
 viewer.pageNavigation=Page Navigation
 viewer.currentPage=Current Page
 viewer.totalPages=Total Pages
+toolPanel.legacy.favorites=Favourites
+toolPanel.legacy.recent=Recently used
+toolPanel.legacy.favorite=Add to favourites
+toolPanel.legacy.unfavorite=Remove from favourites
+toolPanel.legacy.settings.title=Customise appearance
+toolPanel.legacy.settings.iconBackground.label=Tool icon background
+toolPanel.legacy.settings.iconBackground.description=When to show coloured backgrounds behind tool icons
+toolPanel.legacy.settings.iconBackground.none=None
+toolPanel.legacy.settings.iconBackground.hover=On hover
+toolPanel.legacy.settings.iconBackground.always=Always
+toolPanel.legacy.settings.iconColor.label=Tool icon colour
+toolPanel.legacy.settings.iconColor.description=Colour scheme for tool icons
+toolPanel.legacy.settings.iconColor.colored=Coloured
+toolPanel.legacy.settings.iconColor.vibrant=Vibrant
+toolPanel.legacy.settings.iconColor.monochrome=Monochrome
+toolPanel.legacy.settings.sectionTitle.label=Section titles
+toolPanel.legacy.settings.sectionTitle.description=Colour for category section titles
+toolPanel.legacy.settings.sectionTitle.colored=Coloured
+toolPanel.legacy.settings.sectionTitle.neutral=Neutral
+toolPanel.legacy.settings.headerIcon.label=Section header icons
+toolPanel.legacy.settings.headerIcon.description=Colour for Favourites/Recent icons
+toolPanel.legacy.settings.headerIcon.colored=Coloured
+toolPanel.legacy.settings.headerIcon.monochrome=Monochrome
+toolPanel.legacy.settings.headerBadge.label=Section header badges
+toolPanel.legacy.settings.headerBadge.description=Colour for count badges in section headers
+toolPanel.legacy.settings.headerBadge.colored=Coloured
+toolPanel.legacy.settings.headerBadge.neutral=Neutral
+toolPanel.legacy.settings.border.label=Tool item borders
+toolPanel.legacy.settings.border.description=Show borders around tool items
+toolPanel.legacy.settings.border.visible=Visible
+toolPanel.legacy.settings.border.hidden=Hidden
+toolPanel.legacy.settings.hover.label=Hover effect intensity
+toolPanel.legacy.settings.hover.description=How prominent the hover effect should be
+toolPanel.legacy.settings.hover.subtle=Subtle
+toolPanel.legacy.settings.hover.moderate=Moderate
+toolPanel.legacy.settings.hover.prominent=Prominent