[inkly]

A "ZFS" tab in the Storage manager, first step, read only (design: docs/superpowers/specs/2026-11-09-zfs-storage-design.md in ReCasaOS/CasaOS; request: ReCasaOS/CasaOS discussion 66). Needs ReCasaOS/CasaOS-LocalStorage#27 for GET /v1/disks/zfs, /zfs/snapshots and /zfs/io; without it the tab simply does not appear.

• The tab is added last (the places of the other tabs do not move) and only when the box answers available with at least one pool. No ZFS, no tab, no message.
• A card per pool: health tag (green with a check only for ONLINE; DEGRADED orange; the other states and any unknown one red; a pool whose state could not be read is grey "State unknown", never green), layout, drives with the disk they are on, last scan (scrub or resilver, errors count as a problem), data errors, capacity bar (orange from 80 %, red from 90 %), allocated / free / total / fragmentation, live read/write rates, and a "Details" fold with ZFS's own status: / action: lines (English, as ZFS prints them) and the tree of vdevs with their error counters.
• Datasets as a tree: used bar (used / (used + available), as ZFS counts it with quotas), mount point or why not (not mounted, locked, mounted by the system, volume), available, referenced, space held by snapshots.
• Snapshots of a dataset are asked for when its list is opened, once.
• Live rates are the difference between two readings of the pool counters every 3 s; the first reading shows nothing, never "0 B/s".
• Asks the box only while the tab is on show and the page visible: the list every 15 s, the counters every 3 s; nothing once the tab is left or the panel unmounted.
• Texts in en_US.json and fr_FR.json, with a test that every key the ZFS code uses is in both and keeps its placeholders.

Tests: ZfsPanel.spec.js (healthy, degraded, unknown state, ZFS not answering, snapshots on demand, rates, polling stops when the tab is left, keys) and zfs.spec.js (tags, thresholds, tree order, mount text, scan sentences, rates, vdev tree). Full suite green (182 files), eslint 0 errors on the changed files, Node 22 + pnpm.

Not checked: the layout in a browser (no box with ZFS here, and the mock server has no ZFS route); the accompanying LocalStorage fixtures are partly written from the OpenZFS docs, see that PR.