Longhorn 10257: show why a volume isn't ready PR not opened yet

diff --git a/src/routes/volume/VolumeList.js b/src/routes/volume/VolumeList.js
index ea5b1e9..e92128d 100755
--- a/src/routes/volume/VolumeList.js
+++ b/src/routes/volume/VolumeList.js
@@ -6,7 +6,7 @@ import classnames from 'classnames'
 import { LinkTo, EngineImageUpgradeTooltip, ReplicaHATooltip } from '../../components'
 import { formatMib } from '../../utils/formatter'
 import VolumeActions from './VolumeActions'
-import { isSchedulingFailure, getHealthState, needToWaitDone, extractImageVersion } from './helper/index'
+import { isSchedulingFailure, getHealthState, getNotReadyMessage, needToWaitDone, extractImageVersion } from './helper/index'
 import { sortTable, sortTableObject, sortTableByUTCDate, sortTableByPVC, sortTableActualSize, sortTableState, sortTableByTimestamp } from '../../utils/sort'
 import { setSortOrder } from '../../utils/store'
 import { statusUpgradingEngine } from '../../utils/status'
@@ -182,8 +182,7 @@ function list({
           let attachedNode = record.controllers && record.controllers[0] && record.controllers[0].hostId ? record.controllers[0].hostId : ''
           return item.hostId !== attachedNode
         })
-        let statusForWorkloadMessage = `Not ready for workload. ${record.robustness === 'faulted' ? 'Volume Faulted' : 'Volume may be under maintenance or in the restore process.'} `
-        let statusForWorkload = <Tooltip title={statusForWorkloadMessage}><Icon type="exclamation-circle" className="faulted" style={{ marginLeft: 5 }} /></Tooltip>
+        let statusForWorkload = <Tooltip title={getNotReadyMessage(record)}><Icon type="exclamation-circle" className="faulted" style={{ marginLeft: 5 }} /></Tooltip>
         let stateText = (() => {
           if (text.hyphenToHump() === 'attached' && record.robustness === 'healthy') {
             return (<div
diff --git a/src/routes/volume/detail/VolumeInfo.js b/src/routes/volume/detail/VolumeInfo.js
index 2d25988..80f2b32 100644
--- a/src/routes/volume/detail/VolumeInfo.js
+++ b/src/routes/volume/detail/VolumeInfo.js
@@ -7,6 +7,7 @@ import { formatMib } from '../../../utils/formatter'
 import {
   isSchedulingFailure,
   getHealthState,
+  getNotReadyMessage,
   needToWaitDone,
   frontends,
   extractImageVersion,
@@ -232,7 +233,7 @@ function VolumeInfo({ selectedVolume, snapshotModalState, engineImages, hosts, c
       </div>
       <div className={styles.row}>
         <span className={styles.label}> Ready for workload:</span>
-        {selectedVolume.ready ? <span className="healthy">Ready</span> : <Tooltip title={`Not ready for workload. ${selectedVolume.robustness === 'faulted' ? 'Volume Faulted' : 'Volume may be under maintenance or in the restore process.'} `}><span className="faulted">Not Ready</span></Tooltip>}
+        {selectedVolume.ready ? <span className="healthy">Ready</span> : <Tooltip title={getNotReadyMessage(selectedVolume)}><span className="faulted">Not Ready</span></Tooltip>}
       </div>
       <div className={styles.row}>
         <div className={styles.formItem} style={{ display: 'flex' }}>
diff --git a/src/routes/volume/helper/index.js b/src/routes/volume/helper/index.js
index f5180d9..764a740 100644
--- a/src/routes/volume/helper/index.js
+++ b/src/routes/volume/helper/index.js
@@ -768,6 +768,10 @@ export function getHealthState(state) {
   return state.toLowerCase() === 'unknown' ? 'unknown' : state.hyphenToHump()
 }
 
+export function getNotReadyMessage(volume) {
+  return volume.notReadyMessage ? `Not ready for workload: ${volume.notReadyMessage}` : 'Not ready for workload'
+}
+
 export function needToWaitDone(state, replicas) {
   return state === '' || state.endsWith('ing') || replicas.findIndex(item => item.mode.toLowerCase() === 'wo') > -1
 }

### What this PR does / why we need it

When a volume isn't ready for workloads, the volume list and the volume details page show a "Not ready for workload" tooltip, but the UI guessed the cause from the volume health: "Volume Faulted" for a faulted volume, and "Volume may be under maintenance or in the restore process." for anything else.

The manager now returns the real reason with each volume as `notReadyMessage` (https://github.com/longhorn/longhorn-manager/pull/4937). I show it in both tooltips, so they read `Not ready for workload: <reason>`, the same reason the CSI plugin puts in the attach error (`volume ... is not ready for workloads: <reason>`). If the message is empty, the tooltip just says "Not ready for workload".

For example, a volume too big for any disk is detached and faulted. On master the tooltip says "Volume Faulted". With this PR it says "volume is currently in detached state with some un-schedulable replicas".

### Issue

https://github.com/longhorn/longhorn/issues/10257

### Test Result

I tested against a Longhorn master-head cluster:

- A 100 Ti v1 volume that no disk can hold: master shows "Not ready for workload. Volume Faulted" in the volume list and on the details page. This PR shows "Not ready for workload: volume is currently in detached state with some un-schedulable replicas" in both.
- Ready volumes are unchanged: no icon in the list, and "Ready" on the details page.

Before (master), then after (this PR):

(the clip, uploaded once the PR exists)

### Additional documentation or context

UI only. The `notReadyMessage` field comes from the manager change above.

curl -X POST -H 'Content-Type: application/json' $LONGHORN/v1/volumes -d '{"name":"lh10257-unsched","size":"109951162777600","numberOfReplicas":3,"dataEngine":"v1","frontend":"blockdev","accessMode":"rwo"}'
# 100 Ti: no disk can hold a replica → detached + faulted, ready=false
# A 4-replica volume on 3 nodes doesn't work: allow-volume-creation-with-degraded-availability keeps Scheduled True.