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/notifications-svc/Dockerfile

@@ -1,7 +1,9 @@
+# syntax=docker/dockerfile:1
 FROM node:22-alpine AS builder
 WORKDIR /app
 COPY package*.json ./
-RUN npm ci
+COPY --from=npm-cache / /tmp/npm-cache
+RUN npm ci --cache /tmp/npm-cache
 COPY tsconfig.json ./
 COPY src ./src
 COPY drizzle ./drizzle
@@ -10,7 +12,8 @@ RUN npm run build
 FROM node:22-alpine
 WORKDIR /app
 COPY package*.json ./
-RUN npm ci --omit=dev
+COPY --from=npm-cache / /tmp/npm-cache
+RUN npm ci --omit=dev --cache /tmp/npm-cache
 COPY --from=builder /app/dist ./dist
 COPY drizzle ./drizzle
 EXPOSE 3013