Promote AgentCompany-New to the repository root and retire the old app

The legacy application - its src, tests, landing site, promo assets, docs,
release tooling, CI workflows, and root configs - leaves the tree; it stays
reachable in history. Everything under AgentCompany-New moves up unchanged:
same package name, so the production userData/database path is untouched,
and e2e/build scripts already resolved paths relative to the project. The
developer cred.txt stays gitignored at its new location. Full verify:ci
passes from the new root.

src/shared/ids.ts

@@ -0,0 +1,5 @@
+export type EntityId = string;
+
+export function createId(prefix: string): EntityId {
+  return `${prefix}_${crypto.randomUUID().replaceAll("-", "")}`;
+}