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

package.json

@@ -13,6 +13,10 @@
   "author": "",
   "license": "ISC",
   "dependencies": {
+    "@radix-ui/react-dialog": "^1.1.15",
+    "@radix-ui/react-label": "^2.1.8",
+    "@radix-ui/react-select": "^2.2.6",
+    "@radix-ui/react-slider": "^1.3.6",
     "@types/better-sqlite3": "^7.6.13",
     "@types/node": "^25.2.3",
     "@types/papaparse": "^5.5.2",