refactor(tauri): clean up external link helper

- Move use-external-link.ts → utils/external-link.ts (plain function, not a composable)
- Remove non-null assertions on providerDef.keyURL (v-if already guards)
- Remove test scaffolding from production global.d.ts

src/components/chat/ProviderSettings.vue

@@ -16,7 +16,7 @@ import ProviderSelectField from '@/components/chat/ProviderSelectField.vue'
 import { useInputUI } from '@/components/ui/input'
 import { usePopoverUI } from '@/components/ui/popover'
 import { useAIChat } from '@/composables/use-chat'
-import { openExternalLink } from '@/composables/use-external-link'
+import { openExternalLink } from '@/utils/external-link'
 
 const cls = usePopoverUI({ content: 'isolate z-[51] w-64 p-3' })
 
@@ -298,7 +298,7 @@ function clearUnsplashKey() {
                 v-if="providerDef.keyURL"
                 type="button"
                 class="cursor-pointer text-[9px] text-muted underline hover:text-surface"
-                @click="openExternalLink(providerDef.keyURL!)"
+                @click="openExternalLink(providerDef.keyURL as string)"
               >
                 Get API key →
               </button>

src/components/chat/ProviderSetup.vue

@@ -5,7 +5,7 @@ import ProviderSelectField from '@/components/chat/ProviderSelectField.vue'
 import { useInputUI } from '@/components/ui/input'
 import { useAIChat } from '@/composables/use-chat'
 import { ACP_AGENTS } from '@open-pencil/core'
-import { openExternalLink } from '@/composables/use-external-link'
+import { openExternalLink } from '@/utils/external-link'
 import { useI18n } from '@open-pencil/vue'
 
 const { providerID, providerDef, setAPIKey, customBaseURL, customModelID } = useAIChat()
@@ -110,7 +110,7 @@ function save() {
       type="button"
       data-test-id="api-key-get-link"
       class="mt-2.5 cursor-pointer text-[10px] text-muted underline hover:text-surface"
-      @click="openExternalLink(providerDef.keyURL!)"
+      @click="openExternalLink(providerDef.keyURL as string)"
     >
       {{ dialogs.getAPIKey({ provider: providerDef.name }) }}
     </button>

src/global.d.ts

@@ -41,5 +41,4 @@ interface Window {
   // The assignment in EditorView.vue is type-safe; test code uses `!` assertion.
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   __OPEN_PENCIL_STORE__?: any
-  __mocked_window_open?: (url?: string | URL, target?: string) => Window | null
 }

tests/e2e/chat-panel.spec.ts

@@ -232,7 +232,7 @@ test('"Get API key" link opens external URL via window.open', async () => {
   const openedUrls: string[] = []
   await page.exposeFunction('mockWindowOpen', (url: string) => openedUrls.push(url))
   await page.evaluate(() => {
-    window.__mocked_window_open = window.open
+    ;(window as any).__savedOpen = window.open
     window.open = (url: string | URL) => {
       ;(window as any).mockWindowOpen(String(url))
       return null
@@ -248,6 +248,6 @@ test('"Get API key" link opens external URL via window.open', async () => {
 
   // Restore
   await page.evaluate(() => {
-    window.open = window.__mocked_window_open
+    window.open = (window as any).__savedOpen
   })
 })