Add request-scoped context for session.getUser()

Use AsyncLocalStorage to provide request context so services can access
the current user without needing Call passed through every function.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

express/app.ts

@@ -6,6 +6,7 @@ import { match } from "path-to-regexp";
 import { Session } from "./auth";
 import { cli } from "./cli";
 import { contentTypes } from "./content-types";
+import { runWithContext } from "./context";
 import { httpCodes } from "./http-codes";
 import { routes } from "./routes";
 import { services } from "./services";
@@ -75,7 +76,10 @@ routes.forEach((route: Route, _idx: number, _allRoutes: Route[]) => {
         };
 
         try {
-            const retval = await route.handler(req);
+            const retval = await runWithContext(
+                { user: auth.user },
+                () => route.handler(req),
+            );
             return retval;
         } catch (error) {
             // Handle authentication errors