feat(volume-browser): phase 2 - file browser UI

- Browse route: /projects/{id}/volumes/{volId}/browse
- Directory listing with file icons, sizes, dates
- Breadcrumb navigation, click-to-navigate directories
- Download entire volume or folder as ZIP
- Upload files via file picker
- i18n EN/RU for all browser strings

web/src/lib/api.ts

@@ -21,7 +21,8 @@ import type {
 	StandaloneProxy,
 	ValidationResult,
 	Volume,
-	VolumeScopeInfo
+	VolumeScopeInfo,
+	BrowseResult
 } from './types';
 
 // ── Helpers ─────────────────────────────────────────────────────────
@@ -352,6 +353,66 @@ export function deleteVolume(
 	return del<{ deleted: string }>(`/api/projects/${projectId}/volumes/${volId}`);
 }
 
+export function browseVolume(
+	projectId: string,
+	volId: string,
+	params?: { path?: string; stage?: string; tag?: string }
+): Promise<BrowseResult> {
+	const query = new URLSearchParams();
+	if (params?.path) query.set('path', params.path);
+	if (params?.stage) query.set('stage', params.stage);
+	if (params?.tag) query.set('tag', params.tag);
+	const qs = query.toString();
+	return get<BrowseResult>(`/api/projects/${projectId}/volumes/${volId}/browse${qs ? `?${qs}` : ''}`);
+}
+
+export function volumeDownloadUrl(
+	projectId: string,
+	volId: string,
+	params?: { path?: string; stage?: string; tag?: string }
+): string {
+	const query = new URLSearchParams();
+	if (params?.path) query.set('path', params.path);
+	if (params?.stage) query.set('stage', params.stage);
+	if (params?.tag) query.set('tag', params.tag);
+	const token = typeof localStorage !== 'undefined' ? localStorage.getItem('auth_token') : null;
+	if (token) query.set('token', token);
+	const qs = query.toString();
+	return `/api/projects/${projectId}/volumes/${volId}/download${qs ? `?${qs}` : ''}`;
+}
+
+export async function uploadToVolume(
+	projectId: string,
+	volId: string,
+	files: FileList,
+	params?: { path?: string; stage?: string; tag?: string }
+): Promise<{ uploaded: string[]; count: number }> {
+	const query = new URLSearchParams();
+	if (params?.path) query.set('path', params.path);
+	if (params?.stage) query.set('stage', params.stage);
+	if (params?.tag) query.set('tag', params.tag);
+	const qs = query.toString();
+
+	const formData = new FormData();
+	for (let i = 0; i < files.length; i++) {
+		formData.append('files', files[i]);
+	}
+
+	const token = typeof localStorage !== 'undefined' ? localStorage.getItem('auth_token') : null;
+	const headers: Record<string, string> = {};
+	if (token) headers['Authorization'] = `Bearer ${token}`;
+
+	const res = await fetch(`/api/projects/${projectId}/volumes/${volId}/upload${qs ? `?${qs}` : ''}`, {
+		method: 'POST',
+		headers,
+		body: formData,
+	});
+
+	const envelope = await res.json();
+	if (!envelope.success) throw new Error(envelope.error ?? 'Upload failed');
+	return envelope.data;
+}
+
 // ── Event Log ───────────────────────────────────────────────────────
 
 export function fetchEventLog(params?: {