feat(drive): add drive picker in sidebar

- select by default the home drive

frontend/src/lib/api/endpoints/drives.ts

@@ -0,0 +1,15 @@
+/**
+ * Drives endpoints. D0 ships read-only listing; mutations (create / rename /
+ * member changes) land in D2/D3 and will be added here under the same shape.
+ *
+ * Consumers usually go through the `drives` store (`$lib/stores/drives.svelte`)
+ * which dedupes the request and caches the list — touch this module directly
+ * only when bypassing the cache is intentional (e.g. an explicit refresh).
+ */
+import { apiJson } from '$lib/api/client';
+import type { Drive } from '$lib/api/types';
+
+/** `GET /api/drives` — every drive the caller can read, default first by convention. */
+export function listDrives(): Promise<Drive[]> {
+	return apiJson<Drive[]>('/api/drives', { credentials: 'same-origin' });
+}

frontend/src/lib/api/endpoints/folders.ts

@@ -103,11 +103,6 @@ function parseListing(raw: unknown): FolderListing {
 	};
 }
 
-/** Top-level folders for the user; the first entry is the home folder. */
-export function listRootFolders(): Promise<FolderItem[]> {
-	return apiJson<FolderItem[]>('/api/folders', { credentials: 'same-origin' });
-}
-
 export async function getFolder(id: string): Promise<FolderItem> {
 	const folder = await apiJson<FolderItem>(`/api/folders/${id}`, NO_CACHE);
 	rememberFolderName(folder.id, folder.name);

frontend/src/lib/api/types.ts

@@ -196,3 +196,24 @@ export interface SearchResults {
 	query_time_ms: number;
 	sort_by: string;
 }
+
+export type DriveKind = 'personal' | 'shared';
+
+/**
+ * One row from `GET /api/drives`. Mirrors `DriveDto` in
+ * `src/application/dtos/drive_dto.rs`. `default_for_user` is the caller's
+ * id when present, `null`/undefined otherwise — used to pick the default
+ * personal drive without hard-coding name conventions.
+ */
+export interface Drive {
+	id: string;
+	name: string;
+	kind: DriveKind;
+	default_for_user?: string | null;
+	root_folder_id: string;
+	quota_bytes?: number | null;
+	used_bytes: number;
+	policies: Record<string, unknown>;
+	created_at: string;
+	updated_at: string;
+}