feat: Implement public access for tenant content

- Add TenantOptionalAuth middleware to allow access to public content without requiring authentication.
- Introduce ListPublicPublished and PublicDetail methods in the content service to retrieve publicly accessible content.
- Create tenant_public HTTP routes for listing and showing public content, including preview and main asset retrieval.
- Enhance content tests to cover scenarios for public content access and permissions.
- Update specifications to reflect the new public content access features and rules.

backend/app/http/tenant_join/routes.manual.go

@@ -0,0 +1,12 @@
+package tenant_join
+
+func (r *Routes) Path() string {
+	return "/t/:tenantCode/v1"
+}
+
+func (r *Routes) Middlewares() []any {
+	return []any{
+		r.middlewares.TenantResolve,
+		r.middlewares.TenantAuth,
+	}
+}