feat: add mergerfs mover and snapraid integration

New 'Almacenamiento' page with:
- Auto-detection of rsync, mergerfs, snapraid binaries and mergerfs mount
- Configurable pool settings (source/dest, macOS cleanup, rsync flags)
- Mergerfs mover with dry-run preview and live SSE output streaming
- SnapRAID diff/sync/scrub/check with live SSE output
- Async job system (1 concurrent job) with SSE streaming
- Job history table

Backend:
- internal/storage/ package with capabilities, mergerfs, snapraid, jobs
- storage_config and storage_jobs DB tables (migration 0008)
- GET/PUT /api/storage/config, GET /api/storage/capabilities
- POST/GET /api/storage/jobs, GET /api/storage/jobs/{id}/stream
- Storage operations disabled when NASCTL_EXEC_SYSTEM=false

Closes #new-feature

web/src/api.ts

@@ -146,6 +146,58 @@ export interface FilePreview {
   size: number;
 }
 
+export type JobKind =
+  | "mergerfs_preview"
+  | "mergerfs_move"
+  | "snapraid_diff"
+  | "snapraid_sync"
+  | "snapraid_scrub"
+  | "snapraid_check";
+
+export interface StorageCapabilities {
+  rsync: boolean;
+  mergerfs: boolean;
+  mergerfs_mounted: boolean;
+  snapraid: boolean;
+}
+
+export interface StorageConfig {
+  id: number;
+  mover_source: string;
+  mover_dest: string;
+  mover_clean_macos: boolean;
+  mover_remove_source: boolean;
+  mover_inplace: boolean;
+  mover_rsync_options: string;
+  snapraid_content: string;
+  snapraid_data_dirs: string;
+  snapraid_parity_dir: string;
+  snapraid_scrub_plan: number;
+  updated_at: string;
+}
+
+export interface StorageJob {
+  id: number;
+  kind: JobKind;
+  status: "queued" | "running" | "success" | "failed" | "cancelled" | "interrupted";
+  args_json: string;
+  pid: number;
+  started_at: string | null;
+  finished_at: string | null;
+  exit_code: number;
+  output: string;
+  error: string;
+  created_at: string;
+}
+
+export interface StorageEvent {
+  type: "line" | "status" | "end" | "error";
+  line?: string;
+  status?: string;
+  exit_code?: number;
+  message?: string;
+}
+
 export class ApiError extends Error {
   status: number;
   constructor(status: number, message: string) {
@@ -243,6 +295,17 @@ export const api = {
   searchFiles: (path: string, q: string, limit = 100) =>
     request<{ results: SearchHit[] }>(`GET`, `/files/search?path=${encodeURIComponent(path)}&q=${encodeURIComponent(q)}&limit=${limit}`),
   fileDownloadUrl: (path: string) => `/api/files/download?path=${encodeURIComponent(path)}`,
+
+  // storage
+  storageCapabilities: () => request<StorageCapabilities>("GET", "/storage/capabilities"),
+  getStorageConfig: () => request<StorageConfig>("GET", "/storage/config"),
+  updateStorageConfig: (c: Partial<StorageConfig>) => request<StorageConfig>("PUT", "/storage/config", c),
+  listStorageJobs: (limit = 50) => request<{ jobs: StorageJob[] }>("GET", `/storage/jobs?limit=${limit}`),
+  getStorageJob: (id: number) => request<StorageJob>("GET", `/storage/jobs/${id}`),
+  startStorageJob: (kind: JobKind, args?: Record<string, unknown>) =>
+    request<StorageJob>("POST", "/storage/jobs", { kind, args }),
+  cancelStorageJob: (id: number) => request<{ ok: boolean }>("POST", `/storage/jobs/${id}/cancel`),
+  storageJobStreamUrl: (id: number) => `/api/storage/jobs/${id}/stream`,
 };
 
 export function formatBytes(bytes: number): string {