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

docs-site/mkdocs.yml

@@ -214,6 +214,26 @@ nav:
       - Troubleshooting: user-journeys/enterprise/troubleshooting.md
       - Advanced Security: user-journeys/enterprise/advanced-security.md
   - Features:
+    - Today's Workflow:
+      - Overview: features/todays-workflow/overview.md
+      - User Guide: features/todays-workflow/workflow-guide.md
+      - Technical Architecture: features/todays-workflow/technical-architecture.md
+      - API Reference: features/todays-workflow/api-reference.md
+    - SIF & AI Agents:
+      - Overview: features/sif-agents/overview.md
+      - Agent Directory: features/sif-agents/agent-directory.md
+      - Committee System: features/sif-agents/committee-system.md
+      - ContentGuardianAgent: features/sif-agents/content-guardian.md
+    - Team Activity:
+      - Overview: features/team-activity/overview.md
+      - Quality Audit Panel: features/team-activity/quality-audit.md
+      - Trend Signals Panel: features/team-activity/trend-signals.md
+      - Alert System: features/team-activity/alert-system.md
+    - Onboarding System:
+      - Overview: features/onboarding/overview.md
+      - Onboarding Steps: features/onboarding/steps.md
+      - Scheduled Tasks: features/onboarding/scheduler-tasks.md
+      - Technical Reference: features/onboarding/technical-reference.md
     - Backlink Outreach:
       - Overview: features/backlink-outreach/overview.md
       - Workflow Guide: features/backlink-outreach/workflow-guide.md