refactor: convert repository to monorepo with npm workspaces

Restructured the repository into a monorepo to better organize application code
and maintenance scripts.

## Workspace Structure
- web-app: Next.js application (all app code moved from root)
- housekeeping: Database backup and maintenance scripts

## Key Changes
- Moved all application code to web-app/ using git mv
- Moved database scripts to housekeeping/ workspace
- Updated Dockerfile for monorepo build process
- Updated docker-compose files (volume paths: ./web-app/etc/hosts/)
- Updated .gitignore for workspace-level node_modules
- Updated documentation (README.md, CLAUDE.md, CHANGELOG.md)

## Migration Impact
- Root package.json now manages workspaces
- Build commands delegate to web-app workspace
- All file history preserved via git mv
- Docker build process updated for workspace structure

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

web-app/app/lib/pdf/renderBarcode.ts

@@ -0,0 +1,51 @@
+import { BarcodeArray } from './pdf417';
+
+/**
+ * Renders a PDF417 barcode matrix to a canvas and returns it as a data URL.
+ *
+ * This function creates an HTML canvas element, draws the barcode by iterating through
+ * the barcode matrix, and converts the canvas to a base64-encoded PNG data URL that
+ * can be used as an image source.
+ *
+ * @param barcodeMatrix - The barcode array generated by the PDF417 encoder containing
+ *                        the barcode matrix data with dimensions and binary code values
+ * @param blockWidth - The width in pixels of each individual barcode module (bar/space unit)
+ * @param blockHeight - The height in pixels of each individual barcode module (bar/space unit)
+ *
+ * @returns A data URL string (base64-encoded PNG) representing the rendered barcode image,
+ *          suitable for use in an HTML img src attribute
+ *
+ * @example
+ * ```typescript
+ * const pdf417 = createPDF417();
+ * pdf417.init("Hello World", 2, 2);
+ * const barcodeArray = pdf417.getBarcodeArray();
+ * const dataUrl = renderBarcode(barcodeArray, 2, 4);
+ * // dataUrl can now be used: <img src={dataUrl} />
+ * ```
+ */
+export function renderBarcode(barcodeMatrix: BarcodeArray, blockWidth: number, blockHeight: number) {
+  
+  const canvas = document.createElement('canvas');
+  canvas.width = barcodeMatrix.num_cols * blockWidth;
+  canvas.height = barcodeMatrix.num_rows * blockHeight;
+  const ctx = canvas.getContext('2d') as CanvasRenderingContext2D;
+
+  let positionY = 0;
+  for (let row = 0; row < barcodeMatrix.num_rows; row += 1) {
+    let positionX = 0;
+
+    for (let col = 0; col < barcodeMatrix.num_cols; col += 1) {
+      if (barcodeMatrix.bcode[row][col] === 1) {
+        ctx.fillStyle = '#000';
+      } else {
+        ctx.fillStyle = '#FFF';
+      }
+      ctx.fillRect(positionX, positionY, blockWidth, blockHeight);
+      positionX += blockWidth;
+    }
+    positionY += blockHeight;
+  }
+
+  return canvas.toDataURL();
+}