feat(form-fill): FormFill tool with context and UI components for PDF form filling (#5711)

frontend/src/proprietary/tools/formFill/providers/PdfBoxFormProvider.ts

@@ -0,0 +1,32 @@
+/**
+ * PdfBoxFormProvider — Backend API form data provider using PDFBox.
+ *
+ * Delegates form field extraction and filling to the server-side Java
+ * implementation via REST endpoints. This provides full-fidelity form
+ * handling including complex field types, appearance generation, and
+ * proper CJK font support.
+ *
+ * Used in the dedicated formFill tool mode.
+ */
+import type { FormField } from '@proprietary/tools/formFill/types';
+import type { IFormDataProvider } from '@proprietary/tools/formFill/providers/types';
+import {
+  fetchFormFieldsWithCoordinates,
+  fillFormFields,
+} from '@proprietary/tools/formFill/formApi';
+
+export class PdfBoxFormProvider implements IFormDataProvider {
+  readonly name = 'pdfbox';
+
+  async fetchFields(file: File | Blob): Promise<FormField[]> {
+    return fetchFormFieldsWithCoordinates(file);
+  }
+
+  async fillForm(
+    file: File | Blob,
+    values: Record<string, string>,
+    flatten: boolean,
+  ): Promise<Blob> {
+    return fillFormFields(file, values, flatten);
+  }
+}