fix(docker): prevent backend crash loop caused by pdf-parse native deps

pdf-parse@2.4.5 pulls in @napi-rs/canvas (native Skia binary) which
crashes on import in Alpine containers. Moved to lazy require() so the
app starts normally and pdf-parse loads only when PDF conversion is
actually requested.
- Lazy-load pdf-parse in pdfToStatement to avoid startup crash
- Add libc6-compat, fontconfig, freetype to Alpine runner stage
- Increase npm fetch timeouts in both Dockerfiles for slow networks
- Add connectionTimeoutMillis to pg Pool for faster failure detection

backend/src/services/pdfToStatement.ts

@@ -1,4 +1,3 @@
-import { PDFParse } from 'pdf-parse';
 import OpenAI from 'openai';
 import { config } from '../config';
 import type { StatementFile } from '@family-budget/shared';
@@ -64,6 +63,18 @@ export function isPdfConversionError(r: unknown): r is PdfConversionError {
   );
 }
 
+// Lazy-loaded to avoid crashing the app at startup — pdf-parse pulls in
+// @napi-rs/canvas (native Skia binary) which may fail on Alpine.
+let _PDFParse: typeof import('pdf-parse')['PDFParse'] | undefined;
+function loadPDFParse() {
+  if (!_PDFParse) {
+    // eslint-disable-next-line @typescript-eslint/no-require-imports
+    const mod = require('pdf-parse') as typeof import('pdf-parse');
+    _PDFParse = mod.PDFParse;
+  }
+  return _PDFParse;
+}
+
 export async function convertPdfToStatement(
   buffer: Buffer,
 ): Promise<StatementFile | PdfConversionError> {
@@ -77,6 +88,7 @@ export async function convertPdfToStatement(
 
   let text: string;
   try {
+    const PDFParse = loadPDFParse();
     const parser = new PDFParse({ data: buffer });
     const result = await parser.getText();
     text = result.text || '';