fix(i18n): clarify de and en texts, add i18n tests

Review all de and en texts for clear wording. Use informal "du" and one
glossary (Nachweis, Punkte, Spieldauer). Add tests for matching
placeholders, matching hint links and points texts that say earn, not pay.

Refs #41 #42

src/i18n.test.js

@@ -7,6 +7,12 @@ vi.mock('i18next-http-backend', () => ({
     default: {type: 'backend', init() {}, read(language, namespace, callback) { callback(null, {}); }},
 }));
 
+const readTexts = (file) =>
+    JSON.parse(readFileSync(path.resolve(import.meta.dirname, '../public/i18n', file), 'utf8'));
+
+const flatTexts = (value, prefix = '') => Object.entries(value).flatMap(([key, child]) =>
+    (typeof child === 'object' ? flatTexts(child, `${prefix}${key}.`) : [[`${prefix}${key}`, child]]));
+
 describe('translation files', () => {
     it('are loaded under a URL that changes with their content, so no browser keeps an old copy', async () => {
         const {default: i18n} = await import('./i18n.js');
@@ -48,6 +54,29 @@ describe('translation keys', () => {
         const read = (file) => keys(JSON.parse(readFileSync(path.join(dir, file), 'utf8'))).sort();
         expect(read('de.json')).toEqual(read('en.json'));
     });
+
+    it('de_And_En_HaveTheSamePlaceholdersPerKey', () => {
+        const placeholders = (file) => Object.fromEntries(flatTexts(readTexts(file))
+            .map(([key, text]) => [key, (text.match(/\{\{\w+\}\}/g) ?? []).sort()]));
+        expect(placeholders('de.json')).toEqual(placeholders('en.json'));
+    });
+
+    it('hintLinks_AreTheSameInDeAndEn', () => {
+        const hints = (file) => Object.fromEntries(Object.entries(readTexts(file).HINT)
+            .map(([key, text]) => [key, {
+                targets: [...text.matchAll(/\]\(([^)]*)\)/g)].map((match) => match[1]),
+                bold: (text.match(/\*\*/g) ?? []).length,
+            }]));
+        expect(hints('de.json')).toEqual(hints('en.json'));
+    });
+});
+
+describe('points texts', () => {
+    it('pointsTexts_SayEarnNotPay', () => {
+        const texts = (file) => flatTexts(readTexts(file).POINTS).map(([, text]) => text);
+        for (const text of texts('de.json')) expect(text).not.toMatch(/\bzahl|Beweis|bezahlt/);
+        for (const text of texts('en.json')) expect(text).not.toMatch(/\bpays?\b|\bpaid\b/);
+    });
 });
 
 describe('people texts', () => {