feat: Add extensible multi-pipeline integration system

This commit implements a plugin-like pipeline architecture with:

Pipeline Core Package (packages/pipeline-core/):
- BasePipeline abstract class all pipelines implement
- PipelineRegistry for database-backed discovery/management
- PipelineRunner for execution with status tracking
- DashboardConfig contracts for dynamic widget definitions

Database Migration (006_pipeline_registry.sql):
- pipeline.registry table for registered pipelines
- pipeline.executions table for execution history
- Views for execution stats and monitoring

ReviewIQ Pipeline Refactor:
- Implements BasePipeline interface
- Adds get_dashboard_config() with widget definitions
- Adds get_widget_data() methods for all dashboard widgets
- Maintains backward compatibility with Pipeline alias

Generic Pipeline API (api/routes/pipelines.py):
- GET /api/pipelines - List all registered pipelines
- GET /api/pipelines/{id} - Pipeline details
- POST /api/pipelines/{id}/execute - Execute pipeline
- GET /api/pipelines/{id}/dashboard - Dashboard config
- GET /api/pipelines/{id}/widgets/{w} - Widget data
- GET /api/pipelines/{id}/executions - Execution history

Frontend Dynamic Dashboard System:
- DynamicDashboard component renders from config
- WidgetRegistry maps types to components
- Widget components: StatCard, LineChart, BarChart,
  PieChart, DataTable, Heatmap
- Pipeline API client library

Frontend Pipeline Pages:
- /pipelines - List all registered pipelines
- /pipelines/[id] - Dynamic dashboard for pipeline
- /pipelines/[id]/executions - Execution history
- Pipelines nav item in Sidebar

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

web/components/dashboard/widgets/BarChart.tsx

@@ -0,0 +1,106 @@
+'use client';
+
+import {
+  BarChart as RechartsBarChart,
+  Bar,
+  XAxis,
+  YAxis,
+  CartesianGrid,
+  Tooltip,
+  Legend,
+  ResponsiveContainer,
+} from 'recharts';
+import type { WidgetConfig, ChartData, ChartWidgetConfig } from '@/lib/pipeline-types';
+import { WidgetWrapper } from './WidgetWrapper';
+
+interface BarChartWidgetProps {
+  config: WidgetConfig;
+  data: ChartData | null;
+  loading: boolean;
+  error?: string;
+  onRefresh?: () => void;
+}
+
+// Default colors for series
+const DEFAULT_COLORS = [
+  '#3b82f6', // blue
+  '#22c55e', // green
+  '#ef4444', // red
+  '#eab308', // yellow
+  '#8b5cf6', // purple
+  '#ec4899', // pink
+  '#06b6d4', // cyan
+];
+
+/**
+ * Bar chart widget using Recharts.
+ */
+export function BarChartWidget({
+  config,
+  data,
+  loading,
+  error,
+  onRefresh,
+}: BarChartWidgetProps) {
+  const chartConfig = config.config as ChartWidgetConfig;
+  const chartData = data?.data || [];
+
+  return (
+    <WidgetWrapper config={config} loading={loading} error={error} onRefresh={onRefresh}>
+      {chartData.length === 0 ? (
+        <div className="flex items-center justify-center h-full text-gray-500">
+          No data available
+        </div>
+      ) : (
+        <ResponsiveContainer width="100%" height="100%">
+          <RechartsBarChart
+            data={chartData}
+            margin={{ top: 5, right: 20, left: 0, bottom: 5 }}
+          >
+            {chartConfig.show_grid !== false && (
+              <CartesianGrid strokeDasharray="3 3" stroke="#e5e7eb" />
+            )}
+            <XAxis
+              dataKey={chartConfig.x_axis?.key || 'x'}
+              tick={{ fontSize: 12 }}
+              tickLine={false}
+              axisLine={{ stroke: '#e5e7eb' }}
+            />
+            <YAxis
+              tick={{ fontSize: 12 }}
+              tickLine={false}
+              axisLine={{ stroke: '#e5e7eb' }}
+              label={
+                chartConfig.y_axis?.label
+                  ? {
+                      value: chartConfig.y_axis.label,
+                      angle: -90,
+                      position: 'insideLeft',
+                      style: { fontSize: 12 },
+                    }
+                  : undefined
+              }
+            />
+            <Tooltip
+              contentStyle={{
+                backgroundColor: 'white',
+                border: '1px solid #e5e7eb',
+                borderRadius: '0.375rem',
+              }}
+            />
+            {chartConfig.show_legend !== false && <Legend />}
+            {chartConfig.series?.map((series, index) => (
+              <Bar
+                key={series.key}
+                dataKey={series.key}
+                name={series.name}
+                fill={series.color || DEFAULT_COLORS[index % DEFAULT_COLORS.length]}
+                radius={[4, 4, 0, 0]}
+              />
+            ))}
+          </RechartsBarChart>
+        </ResponsiveContainer>
+      )}
+    </WidgetWrapper>
+  );
+}