feat(dashboard): FlowPilot cockpit dashboard + sidebar redesign

- Replace QuickStartPage with FlowPilot-centric dashboard
- Add StartSessionInput with Guided/Chat mode toggle
- Add PendingEscalations, ActiveFlowPilotSessions, PerformanceCards
- Add KnowledgeBaseCards, TeamSummary, RecentFlowPilotSessions
- Every number/card is a portal to its detail page
- Restructure sidebar: Resolve/Knowledge/Insights sections
- Remove redundant nav items (FlowPilot, Flow Editor, Flow Assist, etc.)
- Wire prefill from dashboard input to FlowPilot intake
- Update mobile nav to match new sidebar structure

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/pages/FlowPilotSessionPage.tsx

@@ -1,5 +1,5 @@
 import { useEffect, useState } from 'react'
-import { useParams, useSearchParams } from 'react-router-dom'
+import { useParams, useSearchParams, useLocation } from 'react-router-dom'
 import { Sparkles, Loader2 } from 'lucide-react'
 import { useFlowPilotSession } from '@/hooks/useFlowPilotSession'
 import { FlowPilotIntake, FlowPilotSession, SessionBriefing } from '@/components/flowpilot'
@@ -9,6 +9,8 @@ import { toast } from '@/lib/toast'
 export default function FlowPilotSessionPage() {
   const { sessionId } = useParams<{ sessionId?: string }>()
   const [searchParams, setSearchParams] = useSearchParams()
+  const location = useLocation()
+  const prefill = (location.state as { prefill?: string } | null)?.prefill || ''
   const isPickup = searchParams.get('pickup') === 'true'
   const fp = useFlowPilotSession()
   const [pickingUp, setPickingUp] = useState(false)
@@ -84,7 +86,7 @@ export default function FlowPilotSessionPage() {
   if (!fp.session) {
     return (
       <div className="h-full p-6">
-        <FlowPilotIntake onSubmit={fp.startSession} isLoading={fp.isLoading} />
+        <FlowPilotIntake onSubmit={fp.startSession} isLoading={fp.isLoading} defaultProblem={prefill} />
       </div>
     )
   }