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/test_json_mode.mjs

@@ -0,0 +1,59 @@
+import fs from "fs";
+import { generateObject } from "ai";
+import { createOpenAI } from "@ai-sdk/openai";
+import { ReceiptExtractionSchema } from "../src/lib/schema/receipt.ts";
+
+const envContent = fs.readFileSync(".env.local", "utf-8");
+const apiKeyMatch = envContent.match(/OPENROUTER_API_KEY=([^\r\n]+)/);
+const apiKey = apiKeyMatch ? apiKeyMatch[1].trim() : "";
+
+const demoImgPath = "public/demo/01_aral_tankbeleg_muenchen.jpg";
+const imgBase64 = fs.readFileSync(demoImgPath).toString("base64");
+const dataUrl = `data:image/jpeg;base64,${imgBase64}`;
+
+async function testJsonMode() {
+  console.log("Testing generateObject with mode: 'json' on OpenRouter...");
+
+  const openrouter = createOpenAI({
+    apiKey,
+    baseURL: "https://openrouter.ai/api/v1",
+    headers: {
+      "HTTP-Referer": "http://localhost:3000",
+      "X-Title": "Receipt Scanner to Excel",
+    },
+  });
+
+  const { object } = await generateObject({
+    model: openrouter("openai/gpt-4o-mini"),
+    schema: ReceiptExtractionSchema,
+    mode: "json",
+    messages: [
+      {
+        role: "system",
+        content: `Du bist ein hochpräziser KI-Belegscanner. Extrahiere alle Belegdaten vollständig im vorgegebenen JSON-Format:
+- merchant (name, address, taxId, confidence 0-1)
+- date (isoDate YYYY-MM-DD, time, confidence 0-1)
+- documentType (KASSENBON, RECHNUNG, TANKBELEG, BEWIRTUNGSBELEG, PARKTICKET, SONSTIGES)
+- receiptNumber
+- currency (EUR)
+- totalAmount (value, confidence 0-1)
+- netAmount
+- taxBreakdown (array mit ratePercent, taxAmount, netAmount)
+- lineItems (array mit description, quantity, price, taxRate)
+- suggestedCategory (Bewirtung, Reisekosten & Hotel, Tanken & KFZ, Bürobedarf & IT, Verpflegungsmehraufwand, Material & Einkauf, Sonstiges)
+- validation (isMathValid, isDuplicateSuspected, needsUserReview, reviewField, reviewReason)`,
+      },
+      {
+        role: "user",
+        content: [
+          { type: "text", text: "Extrahiere diesen Beleg vollständig als JSON:" },
+          { type: "image", image: dataUrl },
+        ],
+      },
+    ],
+  });
+
+  console.log("✓ SUCCESS! Extracted Object:\n", JSON.stringify(object, null, 2));
+}
+
+testJsonMode().catch(console.error);