docs: update namespace creation guide and refine examples (#345)

- Add documentation for creating namespaces using the `ac` CLI in `create_namespace.mdx`.
- Remove hardcoded `namespace` fields and flags from DaemonSet and ConfigMap examples to improve clarity and usability.

Author: tossmilestone

docs/en/developer/building_application/application_workloads/deamonset_create.mdx

@@ -49,7 +49,6 @@ apiVersion: apps/v1
 kind: DaemonSet
 metadata:
   name: fluentd-elasticsearch
-  namespace: kube-system
   labels:
     k8s-app: fluentd-logging
 spec:

docs/en/developer/building_application/configuration/add_configmap.mdx

@@ -25,7 +25,6 @@ apiVersion: v1
 kind: ConfigMap
 metadata:
   name: my-app-config
-  namespace: default
 data:
   app_mode: "development"
   feature_flags: "true"
@@ -73,7 +72,6 @@ apiVersion: v1
 kind: ConfigMap
 metadata:
   name: app-config
-  namespace: k-1
 data:
   APP_ENV: "production"
   LOG_LEVEL: "debug"
@@ -116,7 +114,7 @@ kubectl create configmap app-config \
 Or from a file:
 
 ```shell
-kubectl apply -f app-config.yaml -n k-1
+kubectl apply -f app-config.yaml
 ```
 
 ## Operations
@@ -133,9 +131,9 @@ Changes to the ConfigMap will affect the workloads that reference the configurat
 ## View, Edit and Delete by using the CLI
 
 ```shell
-kubectl get configmap app-config -n k-1 -o yaml
-kubectl edit configmap app-config -n k-1
-kubectl delete configmap app-config -n k-1
+kubectl get configmap app-config -o yaml
+kubectl edit configmap app-config
+kubectl delete configmap app-config
 ```
 
 ## Ways to Use a ConfigMap in a Pod

docs/en/developer/building_application/namespace/create_namespace.mdx

@@ -102,7 +102,16 @@ Refer to the official Kubernetes documentation: [Namespaces](https://kubernetes.
 
 9.  Click on **Create**.
 
-## Creating namespace by using CLI
+## Creating namespace in a project by **ac** CLI
+
+To use `ac` command-line tool to create a namespace in a project, run the following command:
+
+```bash
+# Create a namespace in project with specific clusters
+ac adm new-project-namespace <namespace-name> --project <project-name> --cluster <cluster-name>
+```
+
+## Creating namespace by **kubectl**
 
 ### YAML file examples \{#namespace-yaml}