refactor: cleanup skeleton, setup supabase properly

src/app.d.ts

@@ -1,10 +1,20 @@
+import type { Session, SupabaseClient, User } from "@supabase/supabase-js";
+import type { Database } from "./lib/database.d.ts"; // import generated types
+
 // See https://svelte.dev/docs/kit/types#app.d.ts
 // for information about these interfaces
 declare global {
     namespace App {
         // interface Error {}
-        // interface Locals {}
-        // interface PageData {}
+        interface Locals {
+            supabase: SupabaseClient<Database>;
+            safeGetSession: () => Promise<{ session: Session | null; user: User | null }>;
+            session: Session | null;
+            user: User | null;
+        }
+        interface PageData {
+            session: Session | null;
+        }
         // interface PageState {}
         // interface Platform {}
     }