refactor: redesign Session History with tabs + Load More, improve Escalation Queue urgency

Session History:
- Split into AI Sessions / Flow Sessions tabs (AI default)
- Load More pagination (25 per page) instead of 50-item hard cap
- Dynamic problem domain filter from actual session data
- Fix all blue focus rings to ember orange
- Fix badge colors to use design system tokens

Escalation Queue:
- Add wait-time color coding (muted <1h, amber 1-4h, red >4h)
- Sort oldest-first for triage urgency
- Compact right-aligned pickup button
- Widen container, dynamic session count in subtitle
- Fix typos and non-system color tokens

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

frontend/src/components/flowpilot/EscalationQueue.tsx

@@ -3,12 +3,21 @@ import { useNavigate } from 'react-router-dom'
 import { AlertTriangle, Clock, Hash, Ticket, Loader2, RefreshCw } from 'lucide-react'
 import { aiSessionsApi } from '@/api'
 import type { AISessionSummary } from '@/types/ai-session'
+import { timeAgo } from '@/lib/timeAgo'
 
 interface EscalationQueueProps {
   onPickup?: (sessionId: string) => void
+  onCountChange?: (count: number) => void
 }
 
-export function EscalationQueue({ onPickup }: EscalationQueueProps) {
+function waitTimeColor(createdAt: string): string {
+  const hours = (Date.now() - new Date(createdAt).getTime()) / 3_600_000
+  if (hours >= 4) return '#f87171'   // danger
+  if (hours >= 1) return '#fbbf24'   // warning/amber
+  return '#848b9b'                    // muted
+}
+
+export function EscalationQueue({ onPickup, onCountChange }: EscalationQueueProps) {
   const navigate = useNavigate()
   const [sessions, setSessions] = useState<AISessionSummary[]>([])
   const [isLoading, setIsLoading] = useState(true)
@@ -19,7 +28,12 @@ export function EscalationQueue({ onPickup }: EscalationQueueProps) {
     setError(null)
     try {
       const data = await aiSessionsApi.getEscalationQueue()
-      setSessions(data)
+      // Sort oldest-first — longest waiting = most urgent
+      const sorted = [...data].sort(
+        (a, b) => new Date(a.created_at).getTime() - new Date(b.created_at).getTime()
+      )
+      setSessions(sorted)
+      onCountChange?.(sorted.length)
     } catch {
       setError('Failed to load escalation queue')
     } finally {
@@ -29,6 +43,7 @@ export function EscalationQueue({ onPickup }: EscalationQueueProps) {
 
   useEffect(() => {
     loadQueue()
+    // eslint-disable-next-line react-hooks/exhaustive-deps -- load once on mount
   }, [])
 
   const handlePickup = (sessionId: string) => {
@@ -50,7 +65,7 @@ export function EscalationQueue({ onPickup }: EscalationQueueProps) {
   if (error) {
     return (
       <div className="py-12 text-center">
-        <p className="text-sm text-rose-400">{error}</p>
+        <p className="text-sm text-danger">{error}</p>
         <button
           onClick={loadQueue}
           className="mt-2 text-xs text-muted-foreground hover:text-foreground transition-colors"
@@ -80,7 +95,7 @@ export function EscalationQueue({ onPickup }: EscalationQueueProps) {
   return (
     <div className="space-y-3">
       <div className="flex items-center justify-between px-1">
-        <h3 className="font-sans text-xs text-[0.625rem] uppercase tracking-wider text-text-muted">
+        <h3 className="font-sans text-[0.625rem] uppercase tracking-wider text-muted-foreground">
           Awaiting pickup ({sessions.length})
         </h3>
         <button
@@ -93,13 +108,13 @@ export function EscalationQueue({ onPickup }: EscalationQueueProps) {
       </div>
 
       {sessions.map((session) => (
-        <div key={session.id} className="card-interactive p-3 sm:p-4 space-y-3">
+        <div key={session.id} className="card-flat p-3 sm:p-4 space-y-3">
           <div>
             <p className="text-sm font-semibold text-foreground">
               {session.problem_summary || 'Untitled session'}
             </p>
             {session.escalation_reason && (
-              <p className="mt-1 text-xs text-amber-400 line-clamp-2">
+              <p className="mt-1 text-xs text-warning line-clamp-2">
                 Reason: {session.escalation_reason}
               </p>
             )}
@@ -107,7 +122,7 @@ export function EscalationQueue({ onPickup }: EscalationQueueProps) {
 
           <div className="flex flex-wrap items-center gap-x-3 gap-y-1 text-xs text-muted-foreground">
             {session.problem_domain && (
-              <span className="font-sans text-xs rounded-md bg-accent-dim px-1.5 py-0.5 text-[0.5625rem] uppercase tracking-wider text-primary">
+              <span className="font-sans rounded-md bg-accent-dim px-1.5 py-0.5 text-[0.5625rem] uppercase tracking-wider text-accent-text">
                 {session.problem_domain}
               </span>
             )}
@@ -115,24 +130,29 @@ export function EscalationQueue({ onPickup }: EscalationQueueProps) {
               <Hash size={10} />
               {session.step_count} steps
             </span>
-            <span className="flex items-center gap-1">
+            <span
+              className="flex items-center gap-1 font-medium"
+              style={{ color: waitTimeColor(session.created_at) }}
+            >
               <Clock size={10} />
-              {new Date(session.created_at).toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' })}
+              {timeAgo(session.created_at)}
             </span>
             {session.psa_ticket_id && (
-              <span className="flex items-center gap-1 text-primary">
+              <span className="flex items-center gap-1 text-accent-text">
                 <Ticket size={10} />
                 #{session.psa_ticket_id}
               </span>
             )}
           </div>
 
-          <button
-            onClick={() => handlePickup(session.id)}
-            className="w-full min-h-[44px] rounded-lg bg-primary text-white px-4 py-2 text-sm font-semibold hover:brightness-110 active:scale-[0.98] transition-all"
-          >
-            Pick Up Session
-          </button>
+          <div className="flex justify-end">
+            <button
+              onClick={() => handlePickup(session.id)}
+              className="rounded-lg bg-primary text-white px-4 py-2 text-sm font-semibold hover:brightness-110 active:scale-[0.98] transition-all"
+            >
+              Pick Up
+            </button>
+          </div>
         </div>
       ))}
     </div>

frontend/src/pages/EscalationQueuePage.tsx

@@ -1,20 +1,27 @@
+import { useState } from 'react'
 import { AlertTriangle } from 'lucide-react'
 import { EscalationQueue } from '@/components/flowpilot'
 
 export default function EscalationQueuePage() {
+  const [count, setCount] = useState<number | null>(null)
+
   return (
-    <div className="mx-auto max-w-3xl p-6">
+    <div className="mx-auto max-w-4xl p-6">
       <div className="flex items-center gap-3 mb-6">
-        <span className="flex h-8 w-8 items-center justify-center rounded-lg bg-amber-500/10">
-          <AlertTriangle size={16} className="text-amber-400" />
+        <span className="flex h-8 w-8 items-center justify-center rounded-lg bg-warning-dim">
+          <AlertTriangle size={16} className="text-warning" />
         </span>
         <div>
           <h1 className="font-heading text-xl font-bold text-foreground">Escalation Queue</h1>
-          <p className="text-sm text-muted-foreground">Sessions from your team waiting for pickup</p>
+          <p className="text-sm text-muted-foreground">
+            {count !== null && count > 0
+              ? `${count} session${count !== 1 ? 's' : ''} waiting for pickup`
+              : 'Sessions from your team waiting for pickup'}
+          </p>
         </div>
       </div>
 
-      <EscalationQueue />
+      <EscalationQueue onCountChange={setCount} />
     </div>
   )
 }