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

backend/internal/handlers/standardization.go

@@ -0,0 +1,24 @@
+package handlers
+
+import (
+	"git.godopu.com/lab/landing_page/backend/internal/httpx"
+	"git.godopu.com/lab/landing_page/backend/internal/repository"
+	"github.com/gin-gonic/gin"
+)
+
+type StandardizationHandler struct {
+	repo *repository.StandardizationRepository
+}
+
+func NewStandardizationHandler(repo *repository.StandardizationRepository) *StandardizationHandler {
+	return &StandardizationHandler{repo: repo}
+}
+
+func (h *StandardizationHandler) GetStandardsBodies(c *gin.Context) {
+	bodies, err := h.repo.GetStandardsBodiesWithProjects(c.Request.Context())
+	if err != nil {
+		httpx.InternalServerError(c, "Failed to retrieve standards bodies: "+err.Error())
+		return
+	}
+	httpx.OK(c, bodies)
+}