feat: implement create-chat-conversation function with OpenAI integration and Supabase support

- Added CORS handling for the create-chat-conversation function.
- Implemented health check endpoint for the function.
- Created endpoints for managing conversations and messages with OpenAI.
- Added error handling and response formatting for better API usability.
- Introduced utility functions for environment variable management and Supabase client creation.
- Enhanced schema handling for structured responses from OpenAI.
- Implemented conversation archiving and retrieval logic.

supabase/functions/create-chat-conversation/lib/cors.ts

@@ -0,0 +1,12 @@
+export const corsHeaders: Record<string, string> = {
+  "access-control-allow-origin": "*",
+  "access-control-allow-headers":
+    "authorization, x-client-info, apikey, content-type",
+  "access-control-allow-methods": "GET,POST,OPTIONS",
+};
+
+export function withCors(res: Response) {
+  const h = new Headers(res.headers);
+  for (const [k, v] of Object.entries(corsHeaders)) h.set(k, v);
+  return new Response(res.body, { status: res.status, headers: h });
+}