Fix: Update Helm docs to use Kubernetes secrets for API Keys

The archodex helm chart currently only supports using Kubernetes secrets for providing the API key. Updating docs to reflect this and provide more guidance.

Author: ajantrania

src/content/docs/docs/getting-started/kubernetes.mdx

@@ -26,8 +26,8 @@ Agent container runs on each Kubernetes Node.
 - **Chart Repository:** `https://helm.archodex.com`
 - **Chart Name:** `archodex-agent`
 - **Values:**
-  - **`reportApiKey`:** (Optional) The Archodex Report API Key value. When provided, the agent containers will report
-    observations periodically to your Archodex account.
+  - **`reportApiKeySecretName`:** (Optional) The Kubernetes secret containing your Archodex Report API Key. When
+    provided, the agent containers will report observations periodically to your Archodex account.
   - **`serviceEndpoint`:** (Optional) The Archodex Service Endpoint URL. Set this value to the location agent containers
     will send reports to when self-hosting. It must be resolvable within the cluster.
   - **`logReport`:** (Optional) Set to `'false'` to disable logging observations to agent container logs.
@@ -43,7 +43,11 @@ To install the Archodex Agent helm chart in your cluster using the helm CLI, fir
 
 ```sh
 $ helm repo add archodex https://helm.archodex.com
-$ helm install archodex-agent --set reportApiKey=<reportApiKey>
+# (Optional) Create a Kubernetes secret with your Report API Key to send
+# observations to your Archodex account
+$ kubectl create secret generic archodex-api-key --from-literal=value='<reportApiKey>'
+# Install the agent (include --set flag to enable reporting, omit for logging-only mode)
+$ helm install archodex-agent archodex/archodex-agent --set reportApiKeySecretName=archodex-api-key
 ```
 
 ## Observing Individual Workloads