fix: cockpit/flowpilot bugs and redesign view toggle placement

- Fix return type annotation on unified_chat_service.send_chat_message (6→7 tuple)
- Fix stale closure in CockpitPage handleStepComplete auto-advance logic
- Fix IncidentHeader copy link hardcoding /assistant/ path (now uses current URL)
- Wire psaTicketId from session data through to CockpitPage incident header
- Fix FlowPilotAsks showing only first question — add chevron navigation for all
- Redesign ViewToggle: add icons (MessageSquare/LayoutDashboard) and subtitles
- Move view toggle from chatbar toolbar to standalone row above input on dashboard
- Standardize toggle placement across dashboard, FlowPilot, and Cockpit pages

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

frontend/src/hooks/useAssistantSession.ts

@@ -163,6 +163,7 @@ export function useAssistantSession() {
     issue_category: string | null
     triage_hypothesis: string | null
     evidence_items: Array<{ text: string; status: string }> | null
+    psa_ticket_id: string | null
   }) => void) | null>(null)
 
   const selectChat = useCallback(async (chatId: string) => {
@@ -185,6 +186,7 @@ export function useAssistantSession() {
         issue_category: detail.issue_category ?? null,
         triage_hypothesis: detail.triage_hypothesis ?? null,
         evidence_items: detail.evidence_items ?? null,
+        psa_ticket_id: detail.psa_ticket_id ?? null,
       })
       // Restore task lane from server state
       if (detail.pending_task_lane) {