Bugfix — Issue #1440: Test Strategy "Introduction & Background" shows literal i18n keys outside en/ro

Problem

The Introduction & Background chapter page of the Test Strategy (gui/templates/strategy/intro.html) is fully functional — it opens from the ASIDE sub-menu ("Test Strategy → Introduction"), from the hub testStrategy.html (chapter 1 card, Open chapter button) and renders the two content cards (Purpose of the document / Background) — but for the 8 locales other than English and Romanian it displayed raw i18n keys instead of text.

Impact (reproduced in browser):

• ?locale=de rendered document title ts.introHeader, header ts.introHeader, sub ts.introHeaderSub, card titles/bullets ts.introC1Title, ts.introC1a/b/c, ts.introC2Title, ts.introC2a/b/c.
• The hub keys (ts.chapterIntro), the back-link (ts.backToStrategy) and the footer title (ts.header) translated fine in German — only the intro content strings broke.
• English and Romanian rendered correctly.

Repro (browser):

1. http://localhost:8082/login.php, sign in admin/admin.
2. ASIDE → Test Strategy → Introduction (or hub → chapter 1 → Open chapter).
3. In the mainframe, switch the locale switcher to German (or open intro.html?locale=de directly).

Root Cause

gui/templates/strategy/intro.html defines every visible string with data-i18n="ts.intro*" (lines 7, 29-30, 42, 44-46, 50, 52-54, 59). TLi18n.apply() (gui/templates/i18n/i18n.js:148-153) writes TLi18n.t(key) into each element, and t() returns _strings[key] || key (i18n.js:134-135) — for a missing key it returns the literal key string (dev-visible by design).

The content keys ts.introHeader, ts.introHeaderSub, ts.introC1Title, ts.introC1a/b/c, ts.introC2Title, ts.introC2a/b/c existed only in en.json (lines 3364-3373) and ro.json (same lines). The other eight bundles (de/es/fr/it/ja/pt/ru/zh.json) had only the hub keys (ts.chapterIntro / ts.chapterIntroDesc), so loading de.json and applying the translations left the intro strings as literal keys.

Blast radius: the Introduction & Background page (issue #1440). The identical missing-key defect exists on the 19 sibling chapter pages — tracked separately in #1486 (bug) so each chapter issue closes only its own keys; the fix pattern here is the reference implementation for it.

Fix

Branch fix/issue-1440, commit cbb2920f5 (fix(strategy): translate Introduction & Background content keys in all 8 non-en/ro bundles (Refs #1440)) — 8 files, +10 lines each (de, es, fr, it, ja, pt, ru, zh).

For every bundle, the 10 ts.intro* content keys were inserted immediately after the existing ts.chapterIntroDesc entry, with native translations that reuse the wording already approved in that bundle's hub key (ts.chapterIntro/ts.chapterIntroDesc) so the hub card and the chapter page agree. Example (German):

"ts.introHeader": "Einleitung & Hintergrund",
"ts.introHeaderSub": "Kontext und Zweck des Teststrategie-Dokuments",
"ts.introC1Title": "Zweck des Dokuments",
"ts.introC1a": "Definiert den allgemeinen Qualitäts- und Testansatz für das Produkt.",
...

Why this method: minimal and i18n-complete. The page already used TLi18n; nothing in HTML/JS needed to change. Only the 8 bundles that missed the keys were touched; en.json/ro.json were already correct and left untouched. Every bundle was validated with python3 -m json.tool before commit.

Rejected alternatives: (a) removing data-i18n and reverting to hard-coded English — would drop the translations that do exist; (b) changing TLi18n.t() to fall back to the element's HTML default — a global behavioral change affecting ~100 modernized screens; (c) translating only German — would leave 7 locales broken.

Files Changed

• 8× gui/templates/i18n/{de,es,fr,it,ja,pt,ru,zh}.json — +10 translated ts.intro* keys each (80 lines total).
• tmp/TLU_Test_Cases.md — regression suite "Regression — Issue #1440" (15 cases, 15/15 PASS).
• docs/Bugfix-Issue-1440-Introduction-Background-i18n.md — this write-up (mirror, without image lines).
• CHANGELOG — one line under the 2.0.1 key-bugfix section (Refs #1440).

Screenshots

• German (fixed) — intro.html?locale=de renders "Einleitung & Hintergrund" with fully translated cards.
• Chinese (fixed) — intro.html?locale=zh renders "引言与背景" with fully translated cards.

Verification

Post-fix: ?locale=<de,es,fr,it,ja,pt,ru,zh> each render the title, header, sub, both cards and all 6 bullets in the target language with zero literal ts.intro* keys (verified in headless Chrome); en and ro unchanged and still correct. All 10 bundles contain all 10 ts.intro* keys exactly once and pass python3 -m json.tool. events table: no new ERROR/WARNING rows; browser console clean on every locale. Full matrix: tmp/TLU_Test_Cases.md suite 1440 (15/15 PASS).