More free models (#1244)

<!-- This is an auto-generated description by cubic. -->

## Summary by cubic
Adds support for free OpenRouter models and a new “Free (OpenRouter)”
auto option that fails over across free models for reliability. Improves
setup flow and UI with provider cards, a “Free” price badge, and an
OpenRouter setup prompt in chat.

- **New Features**
- Added OpenRouter free models: Qwen3 Coder (free), DeepSeek v3 (free),
DeepSeek v3.1 (free), marked with dollarSigns=0 and a “Free” badge.
- New auto model: “Free (OpenRouter)” that uses a fallback client to
cycle through free models with smart retry on transient errors.
- New SetupProviderCard component and updated SetupBanner with dedicated
Google and OpenRouter setup cards.
- Chat shows an OpenRouter setup prompt when “Free (OpenRouter)” is
selected and OpenRouter isn’t configured.
- New PriceBadge component in ModelPicker to display “Free” or price
tier.
- E2E: added setup flow test and option to show the setup screen in
tests.
- Model updates: added DeepSeek v3.1, updated Kimi K2 to kimi-k2-0905,
migrated providers to LanguageModelV2.

<!-- End of auto-generated description by cubic. -->

src/prompts/inspiration_prompts.tsx

@@ -179,24 +179,6 @@ export const INSPIRATION_PROMPTS = [
     ),
     label: "AI Writing Assistant",
   },
-  {
-    icon: (
-      <svg
-        className="w-5 h-5"
-        fill="none"
-        stroke="currentColor"
-        viewBox="0 0 24 24"
-      >
-        <path
-          strokeLinecap="round"
-          strokeLinejoin="round"
-          strokeWidth={2}
-          d="M14.828 14.828a4 4 0 01-5.656 0M9 10h.01M15 10h.01M21 12a9 9 0 11-18 0 9 9 0 0118 0z"
-        />
-      </svg>
-    ),
-    label: "Emoji Translator",
-  },
   {
     icon: (
       <svg