feat: roll out illustrative empty states across 8 pages with 2 new guide entries

- TreeLibraryPage: split empty state into no-flows (illustration + CTA) vs no-filter-results
- MyAnalyticsPage/TeamAnalyticsPage: add zero-sessions empty state with illustration
- SessionHistoryPage: split into no-sessions (illustration) vs no-filter-results
- StepLibraryBrowser: illustrative empty state when no steps exist
- ScriptTemplateList: replace plain empty state with ScriptIllustration
- MySharesPage: replace icon-based empty state with ShareIllustration
- IntegrationsPage: add IntegrationIllustration above setup form
- Add script-templates and psa-setup guides to guides data
- Add EmptyState vitest tests (7 tests)

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

frontend/src/pages/SessionHistoryPage.tsx

@@ -1,5 +1,5 @@
 import { useEffect, useState, useRef, useCallback } from 'react'
-import { useNavigate, useSearchParams } from 'react-router-dom'
+import { Link, useNavigate, useSearchParams } from 'react-router-dom'
 import { PageMeta } from '@/components/common/PageMeta'
 import { sessionsApi } from '@/api/sessions'
 import { treesApi } from '@/api/trees'
@@ -9,6 +9,7 @@ import { SessionFilters } from '@/components/session/SessionFilters'
 import type { SessionFilterState } from '@/components/session/SessionFilters'
 import { Spinner } from '@/components/common/Spinner'
 import { EmptyState } from '@/components/common/EmptyState'
+import { SessionIllustration } from '@/components/common/EmptyStateIllustrations'
 import { cn } from '@/lib/utils'
 import { toast } from '@/lib/toast'
 import { getSessionResumePath } from '@/lib/routing'
@@ -259,19 +260,32 @@ export function SessionHistoryPage() {
           <Spinner />
         </div>
       ) : sessions.length === 0 ? (
-        <EmptyState
-          title="No sessions found"
-          description={filters.ticketNumber || filters.clientName || filters.treeName || filters.dateRange?.from
-            ? "Try adjusting your filters"
-            : "Complete a flow to see it here"}
-          action={
-            (filters.ticketNumber || filters.clientName || filters.treeName || filters.dateRange?.from) ? (
+        (filters.ticketNumber || filters.clientName || filters.treeName || filters.dateRange?.from) ? (
+          <EmptyState
+            title="No sessions match your filters"
+            description="Try adjusting your search or filters."
+            action={
               <button onClick={handleClearFilters} className="text-foreground hover:underline text-sm">
                 Clear all filters
               </button>
-            ) : undefined
-          }
-        />
+            }
+          />
+        ) : (
+          <EmptyState
+            illustration={<SessionIllustration />}
+            title="Your session history will appear here"
+            description="Every troubleshooting session is recorded with decisions, timing, and outcomes — ready for export or review."
+            action={
+              <Link
+                to="/trees"
+                className="inline-flex items-center gap-2 rounded-[10px] bg-gradient-brand px-5 py-2.5 text-sm font-semibold text-[#101114] shadow-lg shadow-primary/20 hover:opacity-90 active:scale-[0.97] transition-all"
+              >
+                Start a Session
+              </Link>
+            }
+            learnMoreLink="/guides/sessions"
+          />
+        )
       ) : (
         <>
         <div className="space-y-4">