feat(ui): add customizable download table columns

Add persisted column reordering, positional alignment, animated drag feedback, and resize cleanup for the download table. Keep row actions at the trailing edge, preserve RTL/LTR behavior, and include localized column controls and sidebar alignment fixes.

src/utils/downloadTableColumns.ts

@@ -0,0 +1,89 @@
+import type { DownloadSortColumn } from './downloadTableSorting';
+
+export type DownloadTableColumnKey = DownloadSortColumn;
+export type DownloadColumnAlignment = 'left' | 'center' | 'right';
+
+export const DEFAULT_COLUMN_ORDER = [
+  'File Name',
+  'Size',
+  'Status',
+  'Speed',
+  'ETA',
+  'Date Added',
+] as const satisfies readonly DownloadTableColumnKey[];
+
+export const DEFAULT_COLUMN_WIDTHS = [340, 100, 220, 100, 80, 170] as const;
+export const COLUMN_MINIMUMS = [160, 58, 92, 58, 48, 112] as const;
+
+export const COLUMN_WIDTHS_STORAGE_KEY = 'firelink-download-column-widths';
+export const COLUMN_ORDER_STORAGE_KEY = 'firelink-download-column-order';
+export const COLUMN_ALIGNMENTS_STORAGE_KEY = 'firelink-download-column-alignments';
+
+export const DEFAULT_COLUMN_ALIGNMENTS: Record<DownloadTableColumnKey, DownloadColumnAlignment> = {
+  'File Name': 'left',
+  Size: 'left',
+  Status: 'left',
+  Speed: 'left',
+  ETA: 'left',
+  'Date Added': 'left',
+};
+
+export const COLUMN_ALIGNMENT_JUSTIFY: Record<DownloadColumnAlignment, 'flex-start' | 'center' | 'flex-end'> = {
+  left: 'flex-start',
+  center: 'center',
+  right: 'flex-end',
+};
+
+const isColumnKey = (value: unknown): value is DownloadTableColumnKey =>
+  typeof value === 'string' && (DEFAULT_COLUMN_ORDER as readonly string[]).includes(value);
+
+const isColumnAlignment = (value: unknown): value is DownloadColumnAlignment =>
+  value === 'left' || value === 'center' || value === 'right';
+
+export const normalizeColumnOrder = (value: unknown): DownloadTableColumnKey[] => {
+  const seen = new Set<DownloadTableColumnKey>();
+  const normalized: DownloadTableColumnKey[] = [];
+
+  if (Array.isArray(value)) {
+    for (const candidate of value) {
+      if (isColumnKey(candidate) && !seen.has(candidate)) {
+        seen.add(candidate);
+        normalized.push(candidate);
+      }
+    }
+  }
+
+  for (const key of DEFAULT_COLUMN_ORDER) {
+    if (!seen.has(key)) normalized.push(key);
+  }
+
+  return normalized;
+};
+
+export const normalizeColumnWidths = (value: unknown): number[] => {
+  if (!Array.isArray(value) || value.length !== DEFAULT_COLUMN_WIDTHS.length) {
+    return [...DEFAULT_COLUMN_WIDTHS];
+  }
+
+  return value.map((width, index) =>
+    typeof width === 'number' && Number.isFinite(width)
+      ? Math.max(COLUMN_MINIMUMS[index], width)
+      : DEFAULT_COLUMN_WIDTHS[index]
+  );
+};
+
+export const normalizeColumnAlignments = (value: unknown): Record<DownloadTableColumnKey, DownloadColumnAlignment> => {
+  const candidate = value && typeof value === 'object' && !Array.isArray(value)
+    ? value as Partial<Record<DownloadTableColumnKey, unknown>>
+    : {};
+
+  return DEFAULT_COLUMN_ORDER.reduce((alignments, key) => {
+    alignments[key] = isColumnAlignment(candidate[key])
+      ? candidate[key]
+      : DEFAULT_COLUMN_ALIGNMENTS[key];
+    return alignments;
+  }, {} as Record<DownloadTableColumnKey, DownloadColumnAlignment>);
+};
+
+export const columnIndex = (key: DownloadTableColumnKey): number =>
+  DEFAULT_COLUMN_ORDER.indexOf(key);