fix: direct K8s scaling, replicas from K8s API, button labels, modify fetch

- Add ScaleClient using K8s API (like kubectl scale deploy --replicas=N)
  - ScaleDeployment: patch Deployment.Spec.Replicas directly
  - GetDeploymentReplicas: query actual K8s deployment replicas
  - Search by labels then fallback to deployment name match
- Wire ScaleClient to InstanceService via SetScaleClient in main.go
- ModifyModal: fetch full instance detail on open (list excludes values)
- InstanceCard: add text labels to action buttons (Entries/Diag/Modify/Delete)
  - Text visible on sm+ screens, icon-only on xs

frontend/src/features/artifact/instances/components/ModifyModal.tsx

@@ -7,7 +7,7 @@ import React, { useState, useEffect } from "react";
 import { Settings } from "lucide-react";
 import { parse as parseYaml, stringify as stringifyYaml } from "yaml";
 import type { InstanceResponse, UpdateInstanceRequest } from "@/api";
-import { getInstanceValuesDiff } from "@/api";
+import { getInstance, getInstanceValuesDiff } from "@/api";
 import {
   Modal,
   Button,
@@ -45,26 +45,29 @@ export const ModifyModal: React.FC<ModifyModalProps> = ({
   } | null>(null);
   const [diffError, setDiffError] = useState<string | null>(null);
 
-  // Initialize with current values
+  // Fetch full instance detail (list excludes values) and load diff
   useEffect(() => {
     setTag(instance.version || "");
     setDescription("");
 
-    // Parse and display existing values as YAML
-    if (instance.values) {
-      try {
-        const parsedValues = typeof instance.values === 'string'
-          ? JSON.parse(instance.values)
-          : instance.values;
-        setValuesYaml(typeof parsedValues === 'object' ? stringifyYaml(parsedValues) : String(parsedValues));
-      } catch (err) {
-        console.error('[ModifyModal] Failed to parse existing values:', err);
-        setValuesYaml(String(instance.values) || "");
+    const loadFullInstance = async () => {
+      if (instance.clusterId && instance.id) {
+        try {
+          const detail = await getInstance(
+            { clusterId: instance.clusterId, instanceId: instance.id },
+          );
+          // Parse and display existing values as YAML
+          if (detail.values && Object.keys(detail.values).length > 0) {
+            setValuesYaml(stringifyYaml(detail.values));
+          }
+        } catch (err) {
+          console.error('[ModifyModal] Failed to fetch instance detail:', err);
+        }
       }
-    }
+      loadValuesDiff();
+    };
 
-    // Load values diff for reference
-    loadValuesDiff();
+    loadFullInstance();
   }, [instance]);
 
   const loadValuesDiff = async () => {