feat: add toggle to show unvalidated models in model selector (#413)

* feat: add toggle to show unvalidated models in model selector

Add a toggle switch in the model configuration dialog to allow users to
display models that haven't been validated. This helps users who work with
model providers that have disabled their verification endpoints.

Changes:
- Add showUnvalidatedModels field to MultiModelConfig type
- Add setShowUnvalidatedModels method to useModelConfig hook
- Add Switch toggle in model-config-dialog footer
- Update model-selector to filter based on showUnvalidatedModels setting
- Add warning icon for unvalidated models in the selector
- Add i18n translations for en/zh/ja

Closes #410

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* fix: wrap AlertTriangle in span for title attribute

The AlertTriangle icon from lucide-react doesn't support the title prop directly.
Wrapped it in a span element to properly display the tooltip.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

components/model-config-dialog.tsx

@@ -50,6 +50,7 @@ import {
     SelectTrigger,
     SelectValue,
 } from "@/components/ui/select"
+import { Switch } from "@/components/ui/switch"
 import { useDictionary } from "@/hooks/use-dictionary"
 import type { UseModelConfigReturn } from "@/hooks/use-model-config"
 import { formatMessage } from "@/lib/i18n/utils"
@@ -1447,10 +1448,23 @@ export function ModelConfigDialog({
 
                 {/* Footer */}
                 <div className="px-6 py-3 border-t border-border-subtle bg-surface-1/30 shrink-0">
-                    <p className="text-xs text-muted-foreground text-center flex items-center justify-center gap-1.5">
-                        <Key className="h-3 w-3" />
-                        {dict.modelConfig.apiKeyStored}
-                    </p>
+                    <div className="flex items-center justify-between">
+                        <div className="flex items-center gap-2">
+                            <Switch
+                                checked={modelConfig.showUnvalidatedModels}
+                                onCheckedChange={
+                                    modelConfig.setShowUnvalidatedModels
+                                }
+                            />
+                            <Label className="text-xs text-muted-foreground cursor-pointer">
+                                {dict.modelConfig.showUnvalidatedModels}
+                            </Label>
+                        </div>
+                        <p className="text-xs text-muted-foreground flex items-center gap-1.5">
+                            <Key className="h-3 w-3" />
+                            {dict.modelConfig.apiKeyStored}
+                        </p>
+                    </div>
                 </div>
             </DialogContent>