feat(backend,docker,docs): implement Go/Gin/SQLite REST API server, Docker containerization, and architecture specifications

- Implement standalone Go backend API server using Gin and pure-Go SQLite (modernc.org/sqlite)
- Add 11-table schema DDL migrations (000001_init.up.sql) based on DATA_TABLE.md
- Add seed data ingestion tool (cmd/seed) and static TypeScript content exporter (cmd/export-content)
- Add configuration loader (internal/config) supporting environment variables and .env files (HOST, PORT, DB_PATH, GIN_MODE, CORS_ALLOW_ORIGINS, AUTO_MIGRATE)
- Add lightweight multi-stage Dockerfile and docker-compose.yml with persistent SQLite volume
- Add comprehensive architecture specification (ARCHITECTURE.md) and REST API interface specification (API_INTERFACE.md)
- Harmonize frontend publications page to consume isHighlight flag from database-synced content

docker-compose.yml

@@ -0,0 +1,27 @@
+services:
+  anl-backend:
+    build:
+      context: ./backend
+      dockerfile: Dockerfile
+    container_name: anl-backend-api
+    restart: unless-stopped
+    ports:
+      - "8080:8080"
+    environment:
+      - HOST=0.0.0.0
+      - PORT=8080
+      - DB_PATH=/app/data/anl.db
+      - GIN_MODE=release
+      - CORS_ALLOW_ORIGINS=*
+      - AUTO_MIGRATE=true
+    volumes:
+      - anl-db-data:/app/data
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:8080/api/v1/health"]
+      interval: 30s
+      timeout: 3s
+      retries: 3
+
+volumes:
+  anl-db-data:
+    name: anl-sqlite-storage