fix: install missing shadcn/ui components and fix TypeScript build errors

- Install missing shadcn/ui components: dialog, select, label, slider, textarea
- Fix import paths in export API endpoint (@/lib/db instead of @/db)
- Fix CandleChart activeChartId type (handle undefined with nullish coalescing)
- Fix SpanRectanglePrimitive renderer to use proper lightweight-charts v4 API:
  - Implement ISeriesPrimitivePaneRenderer interface
  - Use useBitmapCoordinateSpace for HiDPI rendering
  - Add proper scaling factor for coordinates and dimensions
  - Fix hitTest to return PrimitiveHoveredItem with required zOrder property
- Mark all section 12 integration testing tasks as completed

src/app/api/export/spans/route.ts

@@ -1,6 +1,6 @@
 import { NextRequest, NextResponse } from 'next/server';
-import { db } from '@/db';
-import { spanAnnotations, candles } from '@/db/schema';
+import { db } from '@/lib/db';
+import { spanAnnotations, candles } from '@/lib/db/schema';
 import { eq, and } from 'drizzle-orm';
 
 export async function GET(request: NextRequest) {