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/components/scripts/ScriptTemplateList.tsx

@@ -1,5 +1,7 @@
-import { FileCode, Search } from 'lucide-react'
+import { Search } from 'lucide-react'
 import { useScriptGeneratorStore } from '@/store/scriptGeneratorStore'
+import { EmptyState } from '@/components/common/EmptyState'
+import { ScriptIllustration } from '@/components/common/EmptyStateIllustrations'
 import { TemplateCard } from './TemplateCard'
 
 interface Props {
@@ -52,10 +54,13 @@ export function ScriptTemplateList({ inputValue, onClearSearch, onConfigure }: P
       )
     }
     return (
-      <div className="flex flex-col items-center justify-center gap-3 py-12 text-center px-4">
-        <FileCode size={32} className="text-muted-foreground/40" />
-        <p className="text-sm text-muted-foreground">No templates found</p>
-      </div>
+      <EmptyState
+        illustration={<ScriptIllustration />}
+        title="Automate with script templates"
+        description="Pre-built and custom scripts your team can reference during sessions. PowerShell, bash, and more."
+        learnMoreLink="/guides/script-templates"
+        className="px-4"
+      />
     )
   }