feat: ContentGuardianAgent, onboarding UX, Team Activity action wiring, docs, agent help modal

ContentGuardianAgent consolidation:
- Merge 3 duplicate classes into single source in specialized/content_guardian.py
- Watchdog audit_committee() with heuristic scoring, coverage gaps, overlaps, alerts
- Remove misleading rejection_rate() helper; use acceptance_rate directly
- Integrate audit + alerts + trend signals into today_workflow_service.py

Team Activity page:
- QualityAuditPanel: health ring, per-agent critiques, coverage gaps, overlaps
- TrendSignalsPanel: opportunity cards with urgency/impact/coverage bars
- AlertBanner: persistent dismiss via POST /alerts/{id}/mark-read
- AgentHelpModal: dialog showing all 8 agents with descriptions, tools, schedule
- QualityAuditPanel action buttons: Fill gap -> /content-planning, Resolve overlap, View CTA on alerts/issues
- TrendSignalsPanel action buttons: Create content from this trend -> /blog-writer with trend context state

Onboarding system:
- Step 4 validation: no auto-pass via basic_ready; requires persona data or explicit progression
- Step 5 validation: logs warning on auto-pass without integration data
- OnboardingCompletionService: single DB session, transactional task creation, upsert pattern
- Business-without-website: nullable website_url on SIFIndexingTask and MarketTrendsTask
- DeepCompetitorAnalysisExecutor: 5-min timeout, 10-competitor cap, asyncio.wait_for
- Persona generation: async with 30s timeout, falls back to scheduler
- OnboardingProgressService.reset_onboarding(): resets session + pauses all DB tasks
- OnboardingControlService.reset_onboarding(): also cancels APScheduler jobs
- FinalStep TaskSchedulingPanel: shows scheduled/failed tasks after completion, 8s auto-redirect
- onboarding_completed agent activity event logged to feed

Documentation:
- docs-site/features/onboarding/: overview, steps, scheduler-tasks, technical-reference (4 pages)
- docs-site/mkdocs.yml: added Onboarding System nav section
- docs-site/features/sif-agents/: overview, agent-directory, committee-system, content-guardian (4 pages)
- docs-site/features/team-activity/: overview, quality-audit, trend-signals, alert-system (4 pages)
- docs-site/features/todays-workflow/: updated overview, technical-architecture, workflow-guide, api-reference

backend/app.py

@@ -799,12 +799,13 @@ async def startup_event():
         else:
             logger.info(f"[FEATURE-MODE] Skipping scheduler startup (features: {enabled_features})")
 
-        # Check Wix API key configuration
+        # Check Wix configuration (OAuth-based, API key optional)
         wix_api_key = os.getenv('WIX_API_KEY')
         if wix_api_key:
-            logger.warning(f"✅ WIX_API_KEY loaded ({len(wix_api_key)} chars, starts with '{wix_api_key[:10]}...')")
-        else:
-            logger.warning("⚠️ WIX_API_KEY not found in environment - Wix publishing may fail")
+            logger.info(f"WIX_API_KEY loaded ({len(wix_api_key)} chars)")
+        wix_client_id = os.getenv('WIX_CLIENT_ID')
+        if not wix_client_id:
+            logger.warning("⚠️ WIX_CLIENT_ID not found in environment - Wix OAuth connection will fail")
 
         elapsed = time.time() - startup_start
         logger.info(f"ALwrity backend started successfully in {elapsed:.1f}s")