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)

office-translator-landing-page/components/hero-section.tsx

@@ -1,4 +1,4 @@
-import { FileSpreadsheet, FileText, Presentation } from "lucide-react"
+import { FileSpreadsheet, FileText, FileType, Presentation } from "lucide-react"
 
 export function HeroSection() {
   return (
@@ -13,7 +13,7 @@ export function HeroSection() {
       </h1>
 
       <p className="max-w-xl text-pretty text-base leading-relaxed text-muted-foreground md:text-lg">
-        Upload your Excel, Word, or PowerPoint files and get accurate translations with zero formatting loss.
+        Upload your Excel, Word, PowerPoint, or PDF files — including scanned PDFs, recovered via OCR — and get accurate translations with zero formatting loss.
       </p>
 
       <div className="flex items-center gap-6 pt-2">
@@ -29,6 +29,10 @@ export function HeroSection() {
           <Presentation className="size-4" />
           <span>.pptx</span>
         </div>
+        <div className="flex items-center gap-2 text-sm text-muted-foreground">
+          <FileType className="size-4" />
+          <span>.pdf</span>
+        </div>
       </div>
     </section>
   )