feat: standardize admin form limits and guidance

controllers/aboutUsController.js

@@ -2,10 +2,33 @@ const { addBaseUrlToImages } = require("../utils/imageHelper");
 const AboutUs = require("../models/aboutUs");
 const Blog = require("../models/blog");
 const jsonHelper = require("../utils/jsonHelper");
+const {
+  validateLengthRules,
+  summarizeLengthErrors,
+} = require("../utils/lengthValidation");
+const {
+  ABOUT_US_LENGTH_RULES,
+} = require("../constants/contentLengthRules");
 const writeAuditLog = require("../audit/writeAuditLog");
 const diffObject = require("../audit/diffObject");
 const AUDIT_ACTIONS = require("../constants/auditAction");
 
+const handleLengthValidation = (validation, req, res, options = {}) => {
+  const message =
+    summarizeLengthErrors(validation, 3) || "One or more fields exceed the allowed length.";
+
+  if (options.json) {
+    return res.status(400).json({
+      success: false,
+      error: message,
+      errors: validation.errors,
+    });
+  }
+
+  req.flash("error_msg", message);
+  return res.redirect(options.redirectTo || "/admin/about-us");
+};
+
 /**
  * GET /api/about
  * Lấy dữ liệu About Us (Public API cho website và CMS load dữ liệu)
@@ -110,6 +133,11 @@ exports.updateAbout = async (req, res) => {
     // ✅ Capture BEFORE state
     const beforeData = JSON.parse(JSON.stringify(doc.toObject()));
 
+    const validation = validateLengthRules(updateData, ABOUT_US_LENGTH_RULES);
+    if (!validation.valid) {
+      return handleLengthValidation(validation, req, res, { json: true });
+    }
+
     // Use .set() for better handling of nested objects/arrays in Mongoose
     doc.set(updateData);
     await doc.save();
@@ -210,6 +238,13 @@ exports.update = async (req, res) => {
     // ✅ Capture BEFORE state
     const beforeData = JSON.parse(JSON.stringify(doc.toObject()));
 
+    const validation = validateLengthRules(updateData, ABOUT_US_LENGTH_RULES);
+    if (!validation.valid) {
+      return handleLengthValidation(validation, req, res, {
+        redirectTo: `/admin/about-us?activeTab=${req.query.activeTab || "hero"}`,
+      });
+    }
+
     doc.set(updateData);
     await doc.save();