Style checksum file upload field to match package upload field

- Changed plain file input to styled button with filename display
- Added Select/Remove buttons for checksum file upload
- Updated JavaScript handlers for styled checksum file input
- Updated German translation for new button text

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

assets/js/versions.js

@@ -23,6 +23,11 @@
             $('#upload-version-file-btn').on('click', this.openMediaUploader.bind(this));
             $('#remove-version-file-btn').on('click', this.removeSelectedFile);
 
+            // Checksum file events
+            $('#select-checksum-file-btn').on('click', this.triggerChecksumFileSelect);
+            $('#new_checksum_file').on('change', this.onChecksumFileSelected);
+            $('#remove-checksum-file-btn').on('click', this.removeChecksumFile);
+
             // Listen for product type changes
             $('#product-type').on('change', this.onProductTypeChange);
 
@@ -104,6 +109,40 @@
             // Hide and clear checksum file field
             $('#sha256-hash-row').hide();
             $('#new_checksum_file').val('');
+            $('#selected_checksum_name').text('');
+            $('#remove-checksum-file-btn').hide();
+        },
+
+        /**
+         * Trigger checksum file input click
+         */
+        triggerChecksumFileSelect: function(e) {
+            e.preventDefault();
+            $('#new_checksum_file').trigger('click');
+        },
+
+        /**
+         * Handle checksum file selection
+         */
+        onChecksumFileSelected: function(e) {
+            var file = e.target.files[0];
+            if (file) {
+                $('#selected_checksum_name').text(file.name);
+                $('#remove-checksum-file-btn').show();
+            } else {
+                $('#selected_checksum_name').text('');
+                $('#remove-checksum-file-btn').hide();
+            }
+        },
+
+        /**
+         * Remove selected checksum file
+         */
+        removeChecksumFile: function(e) {
+            e.preventDefault();
+            $('#new_checksum_file').val('');
+            $('#selected_checksum_name').text('');
+            $('#remove-checksum-file-btn').hide();
         },
 
         /**
@@ -216,6 +255,8 @@
                             $('#remove-version-file-btn').hide();
                             $('#sha256-hash-row').hide();
                             $('#new_checksum_file').val('');
+                            $('#selected_checksum_name').text('');
+                            $('#remove-checksum-file-btn').hide();
                         } else {
                             alert(response.data.message || wcLicensedProductVersions.strings.error);
                         }

src/Admin/VersionAdminController.php

@@ -101,7 +101,14 @@ final class VersionAdminController
                     <tr id="sha256-hash-row" style="display: none;">
                         <th><label for="new_checksum_file"><?php esc_html_e('Checksum File', 'wc-licensed-product'); ?></label></th>
                         <td>
-                            <input type="file" id="new_checksum_file" name="new_checksum_file" accept=".sha256,.txt" />
+                            <input type="file" id="new_checksum_file" name="new_checksum_file" accept=".sha256,.txt" style="display: none;" />
+                            <span id="selected_checksum_name" class="selected-file-name"></span>
+                            <button type="button" class="button" id="select-checksum-file-btn">
+                                <?php esc_html_e('Select Checksum File', 'wc-licensed-product'); ?>
+                            </button>
+                            <button type="button" class="button" id="remove-checksum-file-btn" style="display: none;">
+                                <?php esc_html_e('Remove', 'wc-licensed-product'); ?>
+                            </button>
                             <p class="description"><?php esc_html_e('Upload a SHA256 checksum file (.sha256 or .txt) to verify file integrity.', 'wc-licensed-product'); ?></p>
                         </td>
                     </tr>