feat: wire remaining PostHog events across all key user actions (#111)

- export_generated: session copy, copy-for-ticket, download
- ai_feature_used: copilot, assistant chat, session-to-flow, KB accelerator, flow assist
- psa_connected: ConnectWise integration creation
- session_shared: share link creation
- flow_created: troubleshooting editor, procedural editor, session-to-flow

All 9 events from the product analytics plan are now fully wired.

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

frontend/src/pages/KBAcceleratorPage.tsx

@@ -1,6 +1,7 @@
 import { useState, useEffect, useCallback, useRef } from 'react'
 import { useNavigate } from 'react-router-dom'
 import { Sparkles, Loader2 } from 'lucide-react'
+import { analytics } from '@/lib/analytics'
 import { toast } from '@/lib/toast'
 import { kbAcceleratorApi } from '@/api'
 import { UploadScreen } from '@/components/kb-accelerator/UploadScreen'
@@ -64,6 +65,7 @@ export default function KBAcceleratorPage() {
         target_type: targetType,
       })
       setImportId(resp.id)
+      analytics.aiFeatureUsed({ feature: 'kb_accelerator' })
       setPhase('processing')
       startPolling(resp.id)
     } catch (err: unknown) {