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>

drizzle.config.ts

@@ -0,0 +1,21 @@
+import { defineConfig } from "drizzle-kit";
+
+// drizzle-kit does not read `.env.local` the way Next.js does, so without this
+// the fallback below would silently win — and on a machine where another
+// project already owns port 5432, that means migrating the wrong database.
+try {
+  process.loadEnvFile(".env.local");
+} catch {
+  // No .env.local (CI, fresh clone): fall through to the environment as given.
+}
+
+export default defineConfig({
+  schema: "./src/lib/schema/db.ts",
+  out: "./drizzle",
+  dialect: "postgresql",
+  dbCredentials: {
+    url:
+      process.env.DATABASE_URL ||
+      "postgresql://receipt_user:receipt_secure_password@localhost:5432/receipt_scanner",
+  },
+});