✨ feat: Add auth flow (#146)

This adds a simple way to incorporate a centralized authentication flow.

The idea is to have the user, API and SSH (for machine authentication)
all in one place using `openauthjs` + `SST`

We also have a database now :)

> We are using InstantDB as it allows us to authenticate a use with just
the email. Plus it is super simple simple to use _of course after the
initial fumbles trying to design the db and relationships_

packages/core/src/error.ts

@@ -0,0 +1,9 @@
+export class VisibleError extends Error {
+    constructor(
+      public kind: "input" | "auth",
+      public code: string,
+      public message: string,
+    ) {
+      super(message);
+    }
+  }