feat: Go backend, enhanced search, new widgets, Docker deploy

Major changes:
- Add Go backend (backend/) with microservices architecture
- Enhanced master-agents-svc: reranker, content-classifier, stealth-crawler,
  proxy-manager, media-search, fastClassifier, language detection
- New web-svc widgets: KnowledgeCard, ProductCard, ProfileCard, VideoCard,
  UnifiedCard, CardGallery, InlineImageGallery, SourcesPanel, RelatedQuestions
- Improved discover-svc with discover-db integration
- Docker deployment improvements (Caddyfile, vendor.sh, BUILD.md)
- Library-svc: project_id schema migration
- Remove deprecated finance-svc and travel-svc
- Localization improvements across services

Made-with: Cursor

services/web-svc/Dockerfile

@@ -4,13 +4,11 @@ FROM node:22-alpine AS builder
 WORKDIR /app
 COPY package.json package-lock.json ./
 COPY services ./services
-# npm cache — ускоряет npm ci, НЕ трогает билд
-RUN --mount=type=cache,target=/root/.npm \
-    npm ci
+COPY --from=npm-cache / /tmp/npm-cache
+RUN npm ci --cache /tmp/npm-cache
 ENV NEXT_TELEMETRY_DISABLED=1
 ARG API_GATEWAY_URL=http://api-gateway.gooseek:3015
 ENV API_GATEWAY_URL=${API_GATEWAY_URL}
-# БЕЗ cache для .next — иначе старый билд попадает в прод
 RUN npm run build -w web-svc
 
 FROM node:22-alpine AS runner