fix: replace @mui/icons-material with @iconify/react (v0.2.3)

Material-UI icons were not provided as globals by Headlamp, causing
'undefined is not an object (evaluating Ct.createSvgIcon)' errors.

Headlamp provides @iconify/react as a global, so all icon imports have
been replaced with Iconify equivalents:
- ErrorOutline → mdi:alert-circle-outline
- ContentCopy → mdi:content-copy
- Visibility → mdi:eye
- VisibilityOff → mdi:eye-off
- CheckCircle → mdi:check-circle
- Error → mdi:alert-circle
- Warning → mdi:alert
- Add → mdi:plus
- Delete → mdi:delete

Changes:
- Replaced all @mui/icons-material imports with @iconify/react Icon component
- Updated 4 component files (ErrorBoundary, DecryptDialog, EncryptDialog, ControllerStatus)
- Bumped version to 0.2.3
- Bundle size reduced: 358.18 kB (98.04 kB gzipped)
- Checksum: SHA256:03787323abc9430a63433838253b2dd8296d237000acdfe4ce2507678b63125f

This should fix the plugin loading issue and make the sidebar entry appear.

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

headlamp-sealed-secrets/src/components/ControllerStatus.tsx

@@ -5,7 +5,7 @@
  * including reachability, response time, and version information.
  */
 
-import { CheckCircle, Error as ErrorIcon, Warning } from '@mui/icons-material';
+import { Icon } from '@iconify/react';
 import { Box, Chip, Tooltip, Typography } from '@mui/material';
 import React from 'react';
 import { useControllerHealth } from '../hooks/useControllerHealth';
@@ -37,18 +37,18 @@ export function ControllerStatus({
 
   // Build status message and icon
   let statusColor: 'success' | 'error' | 'warning' = 'error';
-  let StatusIcon = ErrorIcon;
+  let statusIcon = 'mdi:alert-circle';
   let statusLabel = 'Unreachable';
   let tooltipText = status.error || 'Controller is unreachable';
 
   if (status.healthy) {
     statusColor = 'success';
-    StatusIcon = CheckCircle;
+    statusIcon = 'mdi:check-circle';
     statusLabel = 'Healthy';
     tooltipText = `Controller is healthy${status.version ? ` (${status.version})` : ''}`;
   } else if (status.reachable) {
     statusColor = 'warning';
-    StatusIcon = Warning;
+    statusIcon = 'mdi:alert';
     statusLabel = 'Unhealthy';
     tooltipText = status.error || 'Controller responded but is not healthy';
   }
@@ -57,7 +57,7 @@ export function ControllerStatus({
     <Box sx={{ display: 'flex', alignItems: 'center', gap: 1 }}>
       <Tooltip title={tooltipText}>
         <Chip
-          icon={<StatusIcon />}
+          icon={<Icon icon={statusIcon} />}
           label={statusLabel}
           color={statusColor}
           size="small"

headlamp-sealed-secrets/src/components/DecryptDialog.tsx

@@ -6,7 +6,7 @@
  */
 
 import { K8s } from '@kinvolk/headlamp-plugin/lib';
-import { ContentCopy as CopyIcon, Visibility, VisibilityOff } from '@mui/icons-material';
+import { Icon } from '@iconify/react';
 import {
   Box,
   Button,
@@ -155,7 +155,7 @@ export function DecryptDialog({ sealedSecret, secretKey, onClose }: DecryptDialo
                     aria-label={showValue ? 'Hide secret value' : 'Show secret value'}
                     title={showValue ? 'Hide secret value' : 'Show secret value'}
                   >
-                    {showValue ? <VisibilityOff /> : <Visibility />}
+                    {showValue ? <Icon icon="mdi:eye-off" /> : <Icon icon="mdi:eye" />}
                   </IconButton>
                   <IconButton
                     onClick={handleCopy}
@@ -163,7 +163,7 @@ export function DecryptDialog({ sealedSecret, secretKey, onClose }: DecryptDialo
                     aria-label="Copy value to clipboard"
                     title="Copy value to clipboard"
                   >
-                    <CopyIcon />
+                    <Icon icon="mdi:content-copy" />
                   </IconButton>
                 </Box>
               ),

headlamp-sealed-secrets/src/components/EncryptDialog.tsx

@@ -6,7 +6,7 @@
  */
 
 import { K8s } from '@kinvolk/headlamp-plugin/lib';
-import { Add as AddIcon, Delete as DeleteIcon, Visibility, VisibilityOff } from '@mui/icons-material';
+import { Icon } from '@iconify/react';
 import {
   Box,
   Button,
@@ -222,7 +222,7 @@ export function EncryptDialog({ open, onClose }: EncryptDialogProps) {
                       aria-label={kv.showValue ? 'Hide password' : 'Show password'}
                       tabIndex={0}
                     >
-                      {kv.showValue ? <VisibilityOff /> : <Visibility />}
+                      {kv.showValue ? <Icon icon="mdi:eye-off" /> : <Icon icon="mdi:eye" />}
                     </IconButton>
                   ),
                 }}
@@ -234,13 +234,13 @@ export function EncryptDialog({ open, onClose }: EncryptDialogProps) {
                 aria-label={`Remove key-value pair ${index + 1}`}
                 title={keyValues.length === 1 ? 'At least one key-value pair is required' : `Remove key-value pair ${index + 1}`}
               >
-                <DeleteIcon />
+                <Icon icon="mdi:delete" />
               </IconButton>
             </Box>
           ))}
 
           <Button
-            startIcon={<AddIcon />}
+            startIcon={<Icon icon="mdi:plus" />}
             onClick={handleAddKeyValue}
             aria-label="Add another key-value pair"
           >

headlamp-sealed-secrets/src/components/ErrorBoundary.tsx

@@ -4,7 +4,7 @@
  * Provides graceful error handling for crypto and API operations
  */
 
-import { ErrorOutline } from '@mui/icons-material';
+import { Icon } from '@iconify/react';
 import { Alert, Box, Button, Typography } from '@mui/material';
 import React, { Component, ReactNode } from 'react';
 
@@ -71,7 +71,7 @@ export class CryptoErrorBoundary extends BaseErrorBoundary {
       <Box p={3}>
         <Alert
           severity="error"
-          icon={<ErrorOutline />}
+          icon={<Icon icon="mdi:alert-circle-outline" />}
           action={
             <Button color="inherit" size="small" onClick={this.handleReset}>
               Retry
@@ -116,7 +116,7 @@ export class ApiErrorBoundary extends BaseErrorBoundary {
       <Box p={3}>
         <Alert
           severity="error"
-          icon={<ErrorOutline />}
+          icon={<Icon icon="mdi:alert-circle-outline" />}
           action={
             <Button color="inherit" size="small" onClick={this.handleReset}>
               Retry
@@ -163,7 +163,7 @@ export class GenericErrorBoundary extends BaseErrorBoundary {
       <Box p={3}>
         <Alert
           severity="error"
-          icon={<ErrorOutline />}
+          icon={<Icon icon="mdi:alert-circle-outline" />}
           action={
             <Button color="inherit" size="small" onClick={this.handleReset}>
               Reload