fix: surface errors and polish UX across Step Library and Batch pages (#92)

- StepLibraryPage: replace silent console.error with toast.error on edit/save
  failures; replace manual setTimeout toast with toast.success helper
- BatchStatusPage: add error state with retry button for failed session loads
  instead of showing ambiguous "No sessions found"
- StepDetailModal: guard clipboard copy against browser denial (no false
  "Copied!" state on permission error); fix dead "See all reviews" button
  with inline expand/collapse toggle
- StepLibraryBrowser: add "Try again" retry button to error state; retry
  increments a counter that re-triggers both load effects

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/components/step-library/StepDetailModal.tsx

@@ -29,6 +29,7 @@ export function StepDetailModal({ stepId, onClose, onInsert }: StepDetailModalPr
   const [isLoading, setIsLoading] = useState(true)
   const [error, setError] = useState<string | null>(null)
   const [copiedCommandIndex, setCopiedCommandIndex] = useState<number | null>(null)
+  const [showAllReviews, setShowAllReviews] = useState(false)
 
   useEffect(() => {
     const loadStepDetails = async () => {
@@ -53,9 +54,13 @@ export function StepDetailModal({ stepId, onClose, onInsert }: StepDetailModalPr
   }, [stepId])
 
   const handleCopyCommand = async (command: string, index: number) => {
-    await navigator.clipboard.writeText(command)
-    setCopiedCommandIndex(index)
-    setTimeout(() => setCopiedCommandIndex(null), 2000)
+    try {
+      await navigator.clipboard.writeText(command)
+      setCopiedCommandIndex(index)
+      setTimeout(() => setCopiedCommandIndex(null), 2000)
+    } catch {
+      // Clipboard access denied — don't show false "Copied!" state
+    }
   }
 
   const handleInsert = () => {
@@ -66,7 +71,8 @@ export function StepDetailModal({ stepId, onClose, onInsert }: StepDetailModalPr
 
   const Icon = step ? stepTypeIcons[step.step_type as keyof typeof stepTypeIcons] : HelpCircle
   const hasRating = step && step.rating_count > 0
-  const topReviews = reviews.filter(r => r.review_text).slice(0, 3)
+  const allTextReviews = reviews.filter(r => r.review_text)
+  const visibleReviews = showAllReviews ? allTextReviews : allTextReviews.slice(0, 3)
 
   return (
     <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/80 backdrop-blur-sm">
@@ -228,18 +234,21 @@ export function StepDetailModal({ stepId, onClose, onInsert }: StepDetailModalPr
               )}
 
               {/* Reviews */}
-              {topReviews.length > 0 && (
+              {visibleReviews.length > 0 && (
                 <div>
                   <div className="mb-2 flex items-center justify-between">
                     <h3 className="text-sm font-semibold text-foreground">Reviews</h3>
-                    {reviews.length > 3 && (
-                      <button className="text-xs text-muted-foreground hover:text-foreground hover:underline">
-                        See all {reviews.length} reviews
+                    {allTextReviews.length > 3 && (
+                      <button
+                        onClick={() => setShowAllReviews(v => !v)}
+                        className="text-xs text-muted-foreground hover:text-foreground hover:underline"
+                      >
+                        {showAllReviews ? 'Show less' : `See all ${allTextReviews.length} reviews`}
                       </button>
                     )}
                   </div>
                   <div className="space-y-3">
-                    {topReviews.map(review => (
+                    {visibleReviews.map(review => (
                       <div key={review.id} className="rounded-lg border border-border bg-accent/50 p-3">
                         <div className="mb-2 flex items-center justify-between">
                           <div className="flex items-center gap-2 text-sm">