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

Dockerfile.backend

@@ -5,6 +5,11 @@ COPY package.json package-lock.json* ./
 COPY shared ./shared
 COPY backend ./backend
 
+# Увеличенные таймауты для нестабильной сети
+RUN npm config set fetch-retry-mintimeout 20000 && \
+    npm config set fetch-retry-maxtimeout 120000 && \
+    npm config set fetch-timeout 300000
+
 RUN npm install
 
 FROM node:20-alpine AS build
@@ -22,6 +27,10 @@ FROM node:20-alpine AS runner
 WORKDIR /app
 ENV NODE_ENV=production
 
+# @napi-rs/canvas (dep of pdf-parse) ships a musl pre-built binary that
+# needs these compatibility / font libraries at runtime.
+RUN apk add --no-cache libc6-compat fontconfig freetype
+
 COPY --from=build /app/backend/dist ./dist
 COPY --from=build /app/backend/package.json ./package.json
 COPY --from=build /app/node_modules ./node_modules