fix(web/channel): stabilize inline priority updates (#6415)

* fix(channel): debounce inline priority updates

* fix(channel): commit spinner edits only on Enter or focus leave

Blurring the inline edit input to the +/- buttons flushed the pending
priority update immediately, bypassing the container focus-containment
check and defeating the debounce. Commit now happens via the container
blur handler or explicitly on Enter. Add unit tests for the priority
update scheduler.

* fix(channel): preserve row identity when priority updates reorder channels

web/src/features/channels/components/numeric-spinner-input.tsx

@@ -25,6 +25,7 @@ import { cn } from '@/lib/utils'
 interface NumericSpinnerInputProps {
   value: number | null | undefined
   onChange: (value: number) => void
+  onCommit?: () => void
   min?: number
   max?: number
   step?: number
@@ -36,6 +37,7 @@ interface NumericSpinnerInputProps {
 export function NumericSpinnerInput({
   value,
   onChange,
+  onCommit,
   min = 0,
   max,
   step = 1,
@@ -96,7 +98,7 @@ export function NumericSpinnerInput({
   const commitValue = () => {
     setEditing(false)
     const num = Number(localValue)
-    if (isNaN(num) || localValue === '' || localValue === '-') {
+    if (Number.isNaN(num) || localValue === '' || localValue === '-') {
       setLocalValue(String(value ?? 0))
       return
     }
@@ -107,10 +109,21 @@ export function NumericSpinnerInput({
     }
   }
 
+  const handleControlBlur = (e: React.FocusEvent<HTMLDivElement>) => {
+    if (
+      e.relatedTarget instanceof Node &&
+      e.currentTarget.contains(e.relatedTarget)
+    ) {
+      return
+    }
+    onCommit?.()
+  }
+
   const handleKeyDown = (e: React.KeyboardEvent) => {
     if (e.key === 'Enter') {
       e.preventDefault()
       commitValue()
+      onCommit?.()
     } else if (e.key === 'Escape') {
       setEditing(false)
       setLocalValue(String(value ?? 0))
@@ -126,6 +139,7 @@ export function NumericSpinnerInput({
         <Label className='text-muted-foreground mr-1.5 text-xs'>{label}</Label>
       )}
       <div
+        onBlur={handleControlBlur}
         className={cn(
           'group/spinner border-input inline-flex h-7 items-center gap-0 rounded-md border transition-colors',
           !disabled && 'hover:bg-muted/60',