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/tenant_scope.go

@@ -0,0 +1,37 @@
+package middleware
+
+import (
+	"context"
+
+	"github.com/gin-gonic/gin"
+
+	"github.com/geo-platform/tenant-api/internal/shared/auth"
+	"github.com/geo-platform/tenant-api/internal/shared/response"
+)
+
+type tenantIDKey struct{}
+
+func TenantScope() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		actor, ok := auth.ActorFromCtx(c.Request.Context())
+		if !ok || actor.TenantID == 0 {
+			response.Error(c, response.ErrUnauthorized(40104, "tenant_scope_missing", "tenant context is required"))
+			c.Abort()
+			return
+		}
+		ctx := WithTenantID(c.Request.Context(), actor.TenantID)
+		c.Request = c.Request.WithContext(ctx)
+		c.Next()
+	}
+}
+
+func WithTenantID(ctx context.Context, tenantID int64) context.Context {
+	return context.WithValue(ctx, tenantIDKey{}, tenantID)
+}
+
+func TenantIDFromCtx(ctx context.Context) int64 {
+	if v, ok := ctx.Value(tenantIDKey{}).(int64); ok {
+		return v
+	}
+	return 0
+}