feat: add tenant and user management with migrations, handlers, and tests

- Implemented tenant and user management features including:
  - Tenant creation and management with associated migrations.
  - User creation and management with associated migrations.
  - Tenant membership management with associated migrations.
  - Platform user roles management with associated migrations.
  - Quota management with associated migrations.
  - Article and template management with associated migrations.
- Added HTTP handlers for templates and workspaces.
- Created tests for protected and public routes.
- Introduced a script to check tenant scope in SQL queries.
- Documented task plan for backend completion and frontend foundation.

server/internal/shared/middleware/request_id.go

@@ -0,0 +1,28 @@
+package middleware
+
+import (
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+)
+
+const RequestIDHeader = "X-Request-ID"
+const requestIDKey = "request_id"
+
+func RequestID() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		rid := c.GetHeader(RequestIDHeader)
+		if rid == "" {
+			rid = uuid.New().String()
+		}
+		c.Set(requestIDKey, rid)
+		c.Header(RequestIDHeader, rid)
+		c.Next()
+	}
+}
+
+func RequestIDFromGin(c *gin.Context) string {
+	if rid, ok := c.Get(requestIDKey); ok {
+		return rid.(string)
+	}
+	return ""
+}