Phase 3 Step 5: Enhanced Dashboard with Charts & Analytics

Implemented dashboard visualizations and statistics API endpoints:

New Features:
- Stats API endpoints (/api/stats/scan-trend, /api/stats/summary)
- Chart.js trending chart showing 30-day scan activity
- Schedules widget displaying next 3 upcoming scheduled scans
- Enhanced Quick Actions with Manage Schedules button

Stats API (web/api/stats.py):
- scan-trend endpoint with configurable days (1-365)
- Summary endpoint for dashboard statistics
- Automatic date range filling with zeros for missing days
- Proper authentication and validation

Dashboard Enhancements (web/templates/dashboard.html):
- Chart.js line chart with dark theme styling
- Real-time schedules widget with human-readable time display
- Auto-refresh for schedules every 30 seconds
- Responsive 8-4 column layout for chart and schedules

Tests (tests/test_stats_api.py):
- 18 comprehensive test cases for stats API
- Coverage for date validation, authentication, edge cases
- Tests for empty data handling and date formatting

Progress: 64% complete (9/14 days)
Next: Step 6 - Scheduler Integration

web/app.py

@@ -317,6 +317,7 @@ def register_blueprints(app: Flask) -> None:
     from web.api.schedules import bp as schedules_bp
     from web.api.alerts import bp as alerts_bp
     from web.api.settings import bp as settings_bp
+    from web.api.stats import bp as stats_bp
     from web.auth.routes import bp as auth_bp
     from web.routes.main import bp as main_bp
 
@@ -331,6 +332,7 @@ def register_blueprints(app: Flask) -> None:
     app.register_blueprint(schedules_bp, url_prefix='/api/schedules')
     app.register_blueprint(alerts_bp, url_prefix='/api/alerts')
     app.register_blueprint(settings_bp, url_prefix='/api/settings')
+    app.register_blueprint(stats_bp, url_prefix='/api/stats')
 
     app.logger.info("Blueprints registered")