fix: comprehensive a11y and contrast QA pass across workbench

Automated QA loop (6 parallel browser agents, 2 rounds) found and fixed
15 accessibility, contrast, and responsive issues across all 8 pages:

- WCAG contrast: light-mode warning (#854d0e), error (#b91c1c), toggle
  off-state (surface-400), connection badge (fg-muted)
- ARIA: mode selector group+pressed, tab pattern ids+labelledby, nav
  and aside labels, dialog focus-return, alert roles on banners
- Responsive: library header flex-wrap, search/button aria-labels
- Focus: NavLink visible ring, dialog close button ring

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ts/data/librarian/docs/09b14acd-6274-48f3-a468-1ef78ec71147.bin

@@ -0,0 +1 @@
+Alice Johnson is a senior engineer at Acme Corporation. Acme develops CloudSync, a cloud storage platform. CloudSync uses Amazon Web Services for hosting.

ts/data/librarian/docs/35befdd5-50f2-4432-a7da-b7d95fcc6ab3.bin

@@ -0,0 +1 @@
+Bob Chen is the CTO of Acme Corporation. Alice reports to Bob. CloudSync was launched in 2024 and competes with Dropbox.

ts/data/librarian/docs/897f90a7-58f4-4466-933c-adf6f8d904ca.bin

@@ -0,0 +1 @@
+Alice Johnson is a senior engineer at Acme Corporation. Acme develops CloudSync, a cloud storage platform. CloudSync uses Amazon Web Services for hosting.

ts/data/librarian/docs/b7bc3c30-65fc-424b-bb8b-6dfeca739250.bin

@@ -0,0 +1 @@
+Bob Chen is the CTO of Acme Corporation. Alice reports to Bob. CloudSync was launched in 2024 and competes with Dropbox.

ts/data/librarian/docs/d2871466-6dbd-46f3-b548-8cffc77c466f.bin

@@ -0,0 +1 @@
+The Eiffel Tower is a wrought-iron lattice tower in Paris, France

ts/data/librarian/librarian-state.json

@@ -0,0 +1,88 @@
+{
+  "documents": {
+    "d2871466-6dbd-46f3-b548-8cffc77c466f": {
+      "kind": "text/plain",
+      "title": "Test Knowledge",
+      "comments": "Test doc",
+      "user": "test",
+      "tags": [
+        "test"
+      ],
+      "documentType": "source",
+      "id": "d2871466-6dbd-46f3-b548-8cffc77c466f",
+      "time": 1775544601926
+    },
+    "2b954221-169b-4297-9d0b-5733676bdd19": {
+      "id": "2b954221-169b-4297-9d0b-5733676bdd19",
+      "time": 1775545730516,
+      "kind": "application/pdf",
+      "title": "Acme Corporation Test Document",
+      "comments": "End-to-end pipeline test",
+      "user": "test",
+      "tags": [
+        "test",
+        "pipeline"
+      ],
+      "documentType": "source"
+    },
+    "09b14acd-6274-48f3-a468-1ef78ec71147": {
+      "id": "09b14acd-6274-48f3-a468-1ef78ec71147",
+      "user": "test",
+      "kind": "text/plain",
+      "title": "Page 1",
+      "parentId": "2b954221-169b-4297-9d0b-5733676bdd19",
+      "documentType": "page",
+      "time": 1775545736563,
+      "comments": "",
+      "tags": []
+    },
+    "b7bc3c30-65fc-424b-bb8b-6dfeca739250": {
+      "id": "b7bc3c30-65fc-424b-bb8b-6dfeca739250",
+      "user": "test",
+      "kind": "text/plain",
+      "title": "Page 2",
+      "parentId": "2b954221-169b-4297-9d0b-5733676bdd19",
+      "documentType": "page",
+      "time": 1775545738656,
+      "comments": "",
+      "tags": []
+    },
+    "5c884d9d-7b96-48c2-826c-7ca21314edf8": {
+      "id": "5c884d9d-7b96-48c2-826c-7ca21314edf8",
+      "time": 1775545966287,
+      "kind": "application/pdf",
+      "title": "Acme Corporation Test Document",
+      "comments": "End-to-end pipeline test",
+      "user": "test",
+      "tags": [
+        "test",
+        "pipeline"
+      ],
+      "documentType": "source"
+    },
+    "897f90a7-58f4-4466-933c-adf6f8d904ca": {
+      "id": "897f90a7-58f4-4466-933c-adf6f8d904ca",
+      "user": "test",
+      "kind": "text/plain",
+      "title": "Page 1",
+      "parentId": "5c884d9d-7b96-48c2-826c-7ca21314edf8",
+      "documentType": "page",
+      "time": 1775545972298,
+      "comments": "",
+      "tags": []
+    },
+    "35befdd5-50f2-4432-a7da-b7d95fcc6ab3": {
+      "id": "35befdd5-50f2-4432-a7da-b7d95fcc6ab3",
+      "user": "test",
+      "kind": "text/plain",
+      "title": "Page 2",
+      "parentId": "5c884d9d-7b96-48c2-826c-7ca21314edf8",
+      "documentType": "page",
+      "time": 1775545974301,
+      "comments": "",
+      "tags": []
+    }
+  },
+  "processing": {},
+  "collections": []
+}

ts/packages/workbench/src/components/layout/root-layout.tsx

@@ -52,7 +52,7 @@ export function RootLayout() {
 
         {/* Connection lost banner */}
         {isDisconnected && (
-          <div className="flex items-center gap-2 border-b border-warning/30 bg-warning/10 px-4 py-2 text-xs text-warning">
+          <div role="alert" className="flex items-center gap-2 border-b border-warning/30 bg-warning/10 px-4 py-2 text-xs text-warning">
             <WifiOff className="h-3.5 w-3.5" />
             <span>Connection lost. Attempting to reconnect...</span>
           </div>

ts/packages/workbench/src/components/layout/sidebar.tsx

@@ -32,7 +32,7 @@ interface NavItemProps {
 
 function NavItem({ to, icon: Icon, label }: NavItemProps) {
   return (
-    <NavLink to={to} className="w-full">
+    <NavLink to={to} className="w-full rounded-lg focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-brand-500 focus-visible:ring-offset-1 focus-visible:ring-offset-surface-50">
       {({ isActive }) => (
         <div
           className={cn(
@@ -72,7 +72,7 @@ function ConnectionBadge() {
           ? "text-warning"
           : isConnected
             ? "text-success"
-            : "text-fg-subtle",
+            : "text-fg-muted",
       )}
     >
       <span
@@ -148,7 +148,7 @@ function FlowSelectorDropdown() {
 
 export function Sidebar() {
   return (
-    <aside className="flex h-screen w-sidebar shrink-0 flex-col border-r border-border bg-surface-50">
+    <aside aria-label="Sidebar" className="flex h-screen w-sidebar shrink-0 flex-col border-r border-border bg-surface-50">
       {/* Logo area */}
       <div className="flex h-14 items-center gap-2 px-4">
         <TestTube2 className="h-5 w-5 text-brand-500" />
@@ -167,7 +167,7 @@ export function Sidebar() {
       <div className="mx-3 border-t border-border" />
 
       {/* Navigation links */}
-      <nav className="flex flex-1 flex-col gap-0.5 overflow-y-auto px-2 py-3">
+      <nav aria-label="Main navigation" className="flex flex-1 flex-col gap-0.5 overflow-y-auto px-2 py-3">
         <NavItem to="/chat" icon={MessageSquareText} label="Chat" />
         <NavItem to="/library" icon={LibraryBig} label="Library" />
         <NavItem to="/graph" icon={Rotate3d} label="Graph" />

ts/packages/workbench/src/components/ui/dialog.tsx

@@ -35,6 +35,17 @@ export function Dialog({
   const titleId = useId();
   const dialogRef = useRef<HTMLDivElement>(null);
 
+  // Save the element that triggered the dialog so we can restore focus on close
+  const triggerRef = useRef<HTMLElement | null>(null);
+  useEffect(() => {
+    if (open) {
+      triggerRef.current = document.activeElement as HTMLElement | null;
+    } else if (triggerRef.current) {
+      triggerRef.current.focus();
+      triggerRef.current = null;
+    }
+  }, [open]);
+
   // Close on Escape key
   useEffect(() => {
     if (!open) return;
@@ -132,7 +143,7 @@ export function Dialog({
           <button
             onClick={onClose}
             aria-label="Close dialog"
-            className="rounded-md p-1 text-fg-subtle hover:bg-surface-200 hover:text-fg"
+            className="rounded-md p-1 text-fg-subtle hover:bg-surface-200 hover:text-fg focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-brand-500"
           >
             <X className="h-4 w-4" />
           </button>

ts/packages/workbench/src/index.css

@@ -130,6 +130,6 @@ html.light {
 
   /* Semantic colors stay vivid but slightly darker for contrast */
   --color-success: #16a34a;
-  --color-warning: #ca8a04;
-  --color-error: #dc2626;
+  --color-warning: #854d0e;
+  --color-error: #b91c1c;
 }

ts/packages/workbench/src/pages/chat.tsx

@@ -251,11 +251,12 @@ export default function ChatPage() {
 
         <div className="flex flex-wrap items-center gap-2">
           {/* Mode selector */}
-          <div className="flex rounded-lg border border-border bg-surface-100 p-0.5">
+          <div role="group" aria-label="Chat mode" className="flex rounded-lg border border-border bg-surface-100 p-0.5">
             {MODES.map((mode) => (
               <button
                 key={mode.value}
                 onClick={() => setChatMode(mode.value)}
+                aria-pressed={chatMode === mode.value}
                 className={cn(
                   "rounded-md px-3 py-1 text-xs font-medium transition-colors",
                   chatMode === mode.value

ts/packages/workbench/src/pages/flows.tsx

@@ -324,6 +324,7 @@ function FlowRow({
             }}
             className="rounded p-1.5 text-fg-subtle hover:bg-error/10 hover:text-error"
             title="Stop flow"
+            aria-label={`Stop flow ${flow.id}`}
           >
             <Square className="h-3.5 w-3.5" />
           </button>
@@ -451,7 +452,7 @@ export default function FlowsPage() {
       )}
 
       {error && (
-        <p className="mb-4 rounded-lg bg-error/10 px-4 py-2 text-sm text-error">
+        <p role="alert" className="mb-4 rounded-lg bg-error/10 px-4 py-2 text-sm text-error">
           {error}
         </p>
       )}

ts/packages/workbench/src/pages/graph.tsx

@@ -500,6 +500,7 @@ export default function GraphPage() {
               value={searchTerm}
               onChange={(e) => setSearchTerm(e.target.value)}
               placeholder="Search nodes..."
+              aria-label="Search nodes"
               className="w-48 rounded-lg border border-border bg-surface-100 py-1.5 pl-8 pr-3 text-xs text-fg placeholder:text-fg-subtle focus:border-brand-500 focus:outline-none focus:ring-1 focus:ring-brand-500"
             />
             {searchTerm && (

ts/packages/workbench/src/pages/knowledge-cores.tsx

@@ -214,6 +214,7 @@ export default function KnowledgeCoresPage() {
                         disabled={actionInProgress === id}
                         className="flex items-center gap-1.5 rounded px-2.5 py-1.5 text-xs font-medium text-brand-400 hover:bg-brand-600/10 disabled:opacity-40"
                         title="Load core"
+                        aria-label={`Load core ${id}`}
                       >
                         {actionInProgress === id ? (
                           <Loader2 className="h-3.5 w-3.5 animate-spin" />
@@ -227,6 +228,7 @@ export default function KnowledgeCoresPage() {
                         disabled={actionInProgress === id}
                         className="flex items-center gap-1.5 rounded px-2.5 py-1.5 text-xs font-medium text-error hover:bg-error/10 disabled:opacity-40"
                         title="Delete core"
+                        aria-label={`Delete core ${id}`}
                       >
                         <Trash2 className="h-3.5 w-3.5" />
                         Delete

ts/packages/workbench/src/pages/library.tsx

@@ -156,6 +156,7 @@ function UploadDialog({
                 e.stopPropagation();
                 setFile(null);
               }}
+              aria-label="Remove selected file"
               className="ml-1 text-fg-subtle hover:text-fg"
             >
               <X className="h-3 w-3" />
@@ -345,7 +346,7 @@ export default function LibraryPage() {
   return (
     <div className="flex h-full flex-col">
       {/* Header */}
-      <div className="mb-6 flex items-center justify-between">
+      <div className="mb-6 flex flex-wrap items-center justify-between gap-2">
         <div className="flex items-center gap-3">
           <LibraryBig className="h-6 w-6 text-brand-400" />
           <h1 className="text-2xl font-bold text-fg">Library</h1>

ts/packages/workbench/src/pages/prompts.tsx

@@ -71,9 +71,9 @@ export default function PromptsPage() {
       {/* Tabs */}
       <div role="tablist" aria-label="Prompt sections" className="mb-4 flex gap-1 rounded-lg bg-surface-100 p-1">
         <button
+          id="tab-templates"
           role="tab"
           aria-selected={activeTab === "templates"}
-          aria-controls="panel-templates"
           onClick={() => setActiveTab("templates")}
           className={cn(
             "flex items-center gap-2 rounded-md px-4 py-2 text-sm font-medium transition-colors",
@@ -86,9 +86,9 @@ export default function PromptsPage() {
           Templates
         </button>
         <button
+          id="tab-system"
           role="tab"
           aria-selected={activeTab === "system"}
-          aria-controls="panel-system"
           onClick={() => setActiveTab("system")}
           className={cn(
             "flex items-center gap-2 rounded-md px-4 py-2 text-sm font-medium transition-colors",
@@ -111,7 +111,7 @@ export default function PromptsPage() {
 
       {/* Templates tab */}
       {activeTab === "templates" && (
-        <div id="panel-templates" role="tabpanel" className="flex flex-1 flex-col gap-4 overflow-hidden">
+        <div id="panel-templates" role="tabpanel" aria-labelledby="tab-templates" className="flex flex-1 flex-col gap-4 overflow-hidden">
           {loading && prompts.length === 0 && (
             <div className="flex items-center justify-center py-12">
               <Loader2 className="mr-2 h-5 w-5 animate-spin text-fg-subtle" />
@@ -201,7 +201,7 @@ export default function PromptsPage() {
 
       {/* System Prompt tab */}
       {activeTab === "system" && (
-        <div id="panel-system" role="tabpanel" className="flex flex-1 flex-col overflow-hidden rounded-lg border border-border">
+        <div id="panel-system" role="tabpanel" aria-labelledby="tab-system" className="flex flex-1 flex-col overflow-hidden rounded-lg border border-border">
           <div className="border-b border-border bg-surface-100 px-4 py-3">
             <h2 className="text-xs font-medium uppercase tracking-wider text-fg-muted">
               System Prompt

ts/packages/workbench/src/pages/settings.tsx

@@ -342,7 +342,7 @@ export default function SettingsPage() {
               onClick={toggleTheme}
               className={cn(
                 "relative inline-flex h-6 w-11 items-center rounded-full transition-colors",
-                isDark ? "bg-brand-600" : "bg-surface-300",
+                isDark ? "bg-brand-600" : "bg-surface-400",
               )}
             >
               <span
@@ -372,7 +372,7 @@ export default function SettingsPage() {
                 onClick={() => updateFeatureSwitches({ [key]: !enabled })}
                 className={cn(
                   "relative inline-flex h-6 w-11 items-center rounded-full transition-colors",
-                  enabled ? "bg-brand-600" : "bg-surface-300",
+                  enabled ? "bg-brand-600" : "bg-surface-400",
                 )}
               >
                 <span className={cn(