Add full application: receipt scanning, auth, billing, and account deletion

Brings the working codebase (Next.js app, auth system, Stripe billing,
Docker/deploy config, tests, docs) into version control on top of the
placeholder initial commit, and adds account self-deletion (Danger Zone
in Settings, password + typed-email confirmation, cascading DB cleanup,
Stripe cancellation) per GDPR right-to-erasure.

Excludes local build caches, node_modules, and internal agent scratch
files; .gitignore hardened to keep those out going forward.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

scripts/cors-register-hook.mjs

@@ -0,0 +1,8 @@
+/**
+ * Registers scripts/cors-resolve-hook.mjs before the main script runs.
+ *
+ * Usage: node --import ./scripts/cors-register-hook.mjs scripts/verify_cors.mjs
+ */
+import { register } from "node:module";
+
+register("./cors-resolve-hook.mjs", import.meta.url);