feat: add OpenRouter support and fix input disabling

- Add OpenRouter provider support with @openrouter/ai-sdk-provider
- Fix input not disabling during 'submitted' state for fast providers
- Apply disable logic to all interactive elements (textarea, buttons, handlers)
- Clean up env.example by removing model examples and separator blocks
- Upgrade zod to v4.1.12 for compatibility with ollama-ai-provider-v2
- Add debug logging for status changes in chat components

package.json

@@ -15,6 +15,7 @@
         "@ai-sdk/google": "^2.0.0",
         "@ai-sdk/openai": "^2.0.19",
         "@ai-sdk/react": "^2.0.22",
+        "@openrouter/ai-sdk-provider": "^1.2.3",
         "@radix-ui/react-dialog": "^1.1.6",
         "@radix-ui/react-scroll-area": "^1.2.3",
         "@radix-ui/react-slot": "^1.1.2",