app: better session id handling

packages/app/src/utils/optional.ts

@@ -0,0 +1,11 @@
+import { dual } from "effect/Function"
+
+export namespace Optional {
+  export const map = dual<
+    <I, O>(f: (value: I) => O) => (opt: I | undefined) => O | undefined,
+    <I, O>(opt: I | undefined, f: (value: I) => O) => O | undefined
+  >(2, (opt, f) => {
+    if (opt === undefined) return undefined
+    return f(opt)
+  })
+}