fix(i18n): add i18n support for custom model feature in ModelSelector (#172)

* feat(models): add custom model name input with provider selector

- Add custom model input field at bottom of model selector modal
- Add provider dropdown to specify target provider for custom model
- Track custom models in app store and display with CUSTOM badge
- Merge custom model into provider group list
- Fix custom provider models being overwritten by API response (keep both)

* Upload screenshot

* fix(i18n): add i18n support for custom model feature in ModelSelector

Replace hardcoded English strings (CUSTOM badge, placeholder, hint) with
vue-i18n t() calls and add corresponding translation keys to all 8 locales
(en, zh, ja, ko, fr, es, de, pt).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: toller892 <892@users.noreply.github.com>
Co-authored-by: Tony <125938283+toller892@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

packages/client/src/stores/hermes/app.ts

@@ -19,6 +19,7 @@ export const useAppStore = defineStore('app', () => {
   const modelGroups = ref<AvailableModelGroup[]>([])
   const selectedModel = ref('')
   const selectedProvider = ref('')
+  const customModels = ref<Record<string, string[]>>({})
   const healthPollTimer = ref<ReturnType<typeof setInterval>>()
   const nodeVersion = ref('')
 
@@ -73,6 +74,13 @@ export const useAppStore = defineStore('app', () => {
       await updateDefaultModel({ default: modelId, provider })
       selectedModel.value = modelId
       selectedProvider.value = provider || ''
+      // Track as custom if not already in the server-fetched list
+      if (provider && !modelGroups.value.find(g => g.provider === provider)?.models.includes(modelId)) {
+        if (!customModels.value[provider]) customModels.value[provider] = []
+        if (!customModels.value[provider].includes(modelId)) {
+          customModels.value[provider] = [...customModels.value[provider], modelId]
+        }
+      }
     } catch (err: any) {
       console.error('Failed to switch model:', err)
     }
@@ -122,6 +130,7 @@ export const useAppStore = defineStore('app', () => {
     updating,
     doUpdate,
     modelGroups,
+    customModels,
     selectedModel,
     selectedProvider,
     streamEnabled,