feat(mongodb): add Compass-style collection import/export

apps/desktop/src/lib/import/importSource.ts

@@ -0,0 +1,25 @@
+export type ImportFileSource = string | File;
+
+export interface UploadedImportSource {
+  sourceRef: string;
+  filePath: string;
+}
+
+export function importSourceDisplayName(source: ImportFileSource): string {
+  return typeof source === "string" ? source.split(/[\\/]/).pop() || source : source.name;
+}
+
+export function importTextDelimiterForName(name: string): string {
+  return name.toLowerCase().endsWith(".tsv") ? "\\t" : ",";
+}
+
+/** Reuse a server-side upload on later previews instead of sending the File again. */
+export function importPreviewInput(uploaded: UploadedImportSource | null | undefined, source: ImportFileSource): { fileOrPath: ImportFileSource; sourceRef: string | null } {
+  if (uploaded?.sourceRef) return { fileOrPath: uploaded.filePath, sourceRef: uploaded.sourceRef };
+  return { fileOrPath: source, sourceRef: null };
+}
+
+export function uploadedImportSourceFromPreview(preview: { sourceRef?: string | null; filePath?: string } | null | undefined): UploadedImportSource | null {
+  if (!preview?.sourceRef || !preview.filePath) return null;
+  return { sourceRef: preview.sourceRef, filePath: preview.filePath };
+}