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_hints.mjs

@@ -0,0 +1,67 @@
+import https from 'https';
+
+const keywords = [
+  // German Core
+  'receipt scanner',
+  'beleg scanner',
+  'belege digitalisieren',
+  'rechnung scanner',
+  'kassenbon scanner',
+  'quittung scanner',
+  'spesen app',
+  'buchhaltung scanner',
+  'datev',
+  'datev scanner',
+  'belegmanager',
+  'haushaltsbuch',
+  'ausgaben tracker',
+  'steuer belege',
+  
+  // English Core
+  'receipt to excel',
+  'receipt scanner to excel',
+  'expense tracker',
+  'receipt keeper',
+  'invoice scanner',
+  'smart receipts',
+  'receipts',
+  'shoeboxed',
+  'expensify',
+  'camscanner',
+  'genius scan'
+];
+
+function fetchHints(term, storefront = '143443') { // 143443 = Germany, 143441 = US
+  return new Promise((resolve) => {
+    const url = `https://search.itunes.apple.com/WebObjects/MZSearchHints.woa/wa/hints?clientApplication=Software&term=${encodeURIComponent(term)}`;
+    https.get(url, {
+      headers: {
+        'User-Agent': 'AppStore/3.0 (iOS; 16.0)',
+        'X-Apple-Store-Front': `${storefront}-1,29`
+      }
+    }, (res) => {
+      let data = '';
+      res.on('data', chunk => data += chunk);
+      res.on('end', () => {
+        try {
+          const json = JSON.parse(data);
+          resolve(json);
+        } catch (e) {
+          resolve(null);
+        }
+      });
+    }).on('error', () => resolve(null));
+  });
+}
+
+async function test() {
+  console.log('Testing hints:');
+  for (const kw of ['beleg', 'kassenbon', 'receipt', 'expense', 'datev', 'spesen', 'rechnung']) {
+    const hintsDE = await fetchHints(kw, '143443');
+    console.log(`DE Hints for "${kw}":`, hintsDE?.hints?.map(h => h.term));
+    const hintsUS = await fetchHints(kw, '143441');
+    console.log(`US Hints for "${kw}":`, hintsUS?.hints?.map(h => h.term));
+  }
+}
+
+test();