feat(sv): Storage · capacity card — ZFS pools, dropped pools, per-CT disk

Read-only Proxmox storage health (same PROXMOX_RO_TOKEN as the cluster card):
ZFS pool health+usage, dropped zfspool storages (the donatello/leonardo SATA
signal), and per-LXC rootfs fill, with a HEALTHY/WATCH/ATTENTION roll-up.
Closes the monitoring gap from the 2026-06-09 audit (C1 + H2 were invisible).
Pure normalizeStorage() unit-tested (4 tests).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lib/api/index.js

@@ -34,6 +34,7 @@ import { router as littleblueRouter } from './routes/littleblue.js';
 import { router as aiUsageRouter } from './routes/ai_usage.js';
 import { router as infraRouter } from './routes/infra.js';
 import { router as clusterRouter } from './routes/cluster.js';
+import { router as storageRouter } from './routes/storage.js';
 import { router as kuttRouter } from './routes/kutt.js';
 
 export function mountApi(app) {
@@ -50,6 +51,7 @@ export function mountApi(app) {
   api.use('/actions', actionsRouter);
   api.use('/infra', infraRouter);
   api.use('/cluster', clusterRouter);
+  api.use('/storage', storageRouter);
   api.use('/little-blue', littleblueRouter);
   api.use('/ai-usage', aiUsageRouter);
   api.use('/projects', projectsRouter);