Stirling 2.0 (#3928)

# Description of Changes

<!--

File context for managing files between tools and views
Optimisation for large files
Updated Split to work with new file system and match Matts stepped
design closer

-->

---

## 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: Anthony Stirling <77850077+Frooodle@users.noreply.github.com>

frontend/src/components/shared/MultiSelectControls.tsx

@@ -0,0 +1,88 @@
+import React from "react";
+import { Box, Group, Text, Button } from "@mantine/core";
+import { useTranslation } from "react-i18next";
+
+interface MultiSelectControlsProps {
+  selectedCount: number;
+  onClearSelection: () => void;
+  onOpenInFileEditor?: () => void;
+  onOpenInPageEditor?: () => void;
+  onAddToUpload?: () => void;
+  onDeleteAll?: () => void;
+}
+
+const MultiSelectControls = ({
+  selectedCount,
+  onClearSelection,
+  onOpenInFileEditor,
+  onOpenInPageEditor,
+  onAddToUpload,
+  onDeleteAll
+}: MultiSelectControlsProps) => {
+  const { t } = useTranslation();
+
+  if (selectedCount === 0) return null;
+
+  return (
+    <Box mb="md" p="md" style={{ backgroundColor: 'var(--mantine-color-blue-0)', borderRadius: 8 }}>
+      <Group justify="space-between">
+        <Text size="sm">
+          {selectedCount} {t("fileManager.filesSelected", "files selected")}
+        </Text>
+        <Group>
+          <Button
+            size="xs"
+            variant="light"
+            onClick={onClearSelection}
+          >
+            {t("fileManager.clearSelection", "Clear Selection")}
+          </Button>
+          
+          {onAddToUpload && (
+            <Button
+              size="xs"
+              color="green"
+              onClick={onAddToUpload}
+            >
+              {t("fileManager.addToUpload", "Add to Upload")}
+            </Button>
+          )}
+          
+          {onOpenInFileEditor && (
+            <Button
+              size="xs"
+              color="orange"
+              onClick={onOpenInFileEditor}
+              disabled={selectedCount === 0}
+            >
+              {t("fileManager.openInFileEditor", "Open in File Editor")}
+            </Button>
+          )}
+          
+          {onOpenInPageEditor && (
+            <Button
+              size="xs"
+              color="blue"
+              onClick={onOpenInPageEditor}
+              disabled={selectedCount === 0}
+            >
+              {t("fileManager.openInPageEditor", "Open in Page Editor")}
+            </Button>
+          )}
+          
+          {onDeleteAll && (
+            <Button
+              size="xs"
+              color="red"
+              onClick={onDeleteAll}
+            >
+              {t("fileManager.deleteAll", "Delete All")}
+            </Button>
+          )}
+        </Group>
+      </Group>
+    </Box>
+  );
+};
+
+export default MultiSelectControls;