feat(translation): quality pipeline overhaul + new features (audit 2026-08-29)

Translation quality & format preservation:
- Word: merge adjacent same-format runs into one unit (sentence-level
  coherence like inline-tag handling); translate comments/balloons;
  dedupe textbox collection (was translated twice); RTL no longer
  overrides center/justify alignment; CJK/Arabic font hints (eastAsia/cs)
- PPTX: chart translations now actually reach the output file
  (ChartPart.blob is read-only — rewrite chart XML in the saved ZIP);
  CJK typeface hints (a:ea)
- Excel: sheet renames no longer break references — rewrite cell
  formulas (3D/quoted), defined names, data validations, cond. formats
- PDF: bold/italic honored (hebo/heit/hebi); table cells never merge;
  unchanged blocks left untouched (typography preserved, fixes duplicate
  hyperlinks); attempted/changed stats + route gate now cover PDF;
  CJK font paths; scanned PDFs via Mistral OCR (detection + admin settings)

Features:
- formality param (formal/informal) + automatic regional-variant prompts
- output_mode=bilingual docx (source above translation)
- per-user translation memory on Redis (falls back to LRU), context-hashed
- QA report + 0-100 confidence score in job status; L0 on by default
- OpenAI-compatible providers: whole chunk in ONE numbered-JSON request
  (~15x fewer calls) with per-item fallback; base prompt always present
  (custom prompt no longer replaces translation instructions)

Infra & marketing alignment:
- plan-based engine gating + vision gating (closes paid-engine leak);
  /providers/available filtered per plan; 107 languages exposed
- zh-CN/zh-TW validation fixed; libmagic disabled on Windows (native crash)
- admin: Mistral OCR settings + engine status dashboard; httpx<0.28 pin
  (TestClient breakage); Prometheus test fixture fixed
- marketing docs aligned with code (PDF+OCR, retention, engines, pricing)
- security: .env.ionos/.env.production/provider_settings.json removed

Tests: 1173 passed / 0 failed (6 network tests deselected: free Google
endpoint temporarily blocked from this machine)

docs/marketing/launch/show-hn.md

@@ -0,0 +1,31 @@
+# Hacker News — Show HN
+
+> Statut : prêt à publier (Phase 2, J0 matin EST). Soumettre via « Show HN » — pas de self-upvote.
+
+## Titre
+**Show HN: Office document translation that preserves the formatting**
+
+## Corps
+> I built **Office Translator** (Wordly.art) because every document translator I used — Google, DeepL, the one-shot tools — destroyed the layout. Translating a 50-page Excel pricing matrix meant getting back a text dump: merged cells gone, formulas replaced by computed values, slide decks unrecognizable. The translation was 5% of the job; fixing the format was 95%.
+>
+> So I made the format-preservation the product:
+>
+> - **In-place translation** for .xlsx / .docx / .pptx / .pdf. The pipeline parses the native structure (cells + merges + formulas, paragraph runs + styles, slide XML + shapes), extracts only translatable content, translates it, and writes it back into the *same* structure. Output looks like it was authored in the target language.
+> - **Scanned PDFs work too**: image-only pages are recovered with OCR (Mistral) before translation — most competitors (DeepL, Azure) reject those outright.
+> - **7 engines, user's choice per document**: Google (free), DeepL, Google Cloud, OpenRouter LLMs in two tiers (DeepSeek / Gemini / Claude), OpenAI, and Grok (xAI). Cheap engine for drafts, premium LLM for client deliverables.
+> - **Custom glossaries** to lock technical/legal/medical terminology across documents.
+> - **Vision translation** for text inside images (paid plans).
+> - **Privacy**: uploads deleted after 30 min, results auto-deleted within 2 hours, zero data retention, content never used for training.
+> - **API** on the Business plan (10k calls/mo) — the web workflow is fully mirrored: submit file, poll job, download.
+>
+> Stack: FastAPI (Python 3.11), openpyxl / python-docx / python-pptx, PyMuPDF, Postgres + Redis, Stripe, Docker, Next.js 15 frontend.
+>
+> Free plan: 2 documents/month, no card. I'd love feedback from people who've worked on document-format-preserving pipelines — what edge cases do I not handle yet? (PDF incl. scanned/OCR is already in — next candidates are IDML and CSV.)
+>
+> https://wordly.art
+
+## Notes de publication
+- Soumettre à 8–9 h EST, mardi–jeudi
+- Répondre à chaque commentaire dans les 2 h ; rester technique, pas commercial
+- Pas de « upvote my post » — c'est interdit sur HN
+- Préparer 2–3 réponses techniques de poches : formule Excel + localisation (format de nombre), fusion de cellules + traduction, gestion des runs mixtes (gras/italique au milieu d'un paragraphe)