feat(modality): rename "file" modality label "Data" -> "Files"

The fifth user-facing group is now Image, Video, Audio, PDF, Files
(internal modality id stays "file"; section.ts "files" was already
"Files"). Updates modality.ts label + comment, all 21 i18n locales
(categories.data "Data Files"->"Files", modalities.documentsAndFiles
"PDF & Data"->"PDF & Files", dead homePage.data), landing cards/hero
search/tools filter, docs headings, and e2e modality-tab assertions
(/^Data/ -> /^Files/, which had been failing).

apps/docs/api/rest.md

@@ -314,7 +314,7 @@ All AI tools run on your hardware (CPU or NVIDIA GPU). No internet required.
 | `to-epub` | Convert to EPUB | - (accepts .docx, .md, .html, .txt) |
 | `ocr-pdf` | PDF OCR (AI) | `quality` (fast/balanced/best), `language` (auto/en/de/fr/es/zh/ja/ko), `pages` |
 
-### Data Tools
+### File Tools
 
 | Tool ID | Name | Key settings |
 |---------|------|-------------|

apps/docs/guide/getting-started.md

@@ -117,7 +117,7 @@ pnpm dev
 | **Video** | 29 | Trim, Crop, Compress, Convert, Merge, Extract Audio, Auto Subtitles, Video to GIF, Resize, Stabilize |
 | **Audio** | 17 | Trim, Merge, Convert, Normalize, Noise Reduction, Transcribe, Pitch Shift, Fade, Ringtone Maker |
 | **PDF / Document** | 37 | Merge, Split, Compress, OCR, Watermark, Redact, Word to PDF, Excel to PDF, Rotate, Protect, Repair |
-| **Data** | 10 | CSV to JSON, JSON to XML, Merge CSVs, Split CSV, Create ZIP, Extract ZIP, Chart Maker, YAML/JSON |
+| **Files** | 10 | CSV to JSON, JSON to XML, Merge CSVs, Split CSV, Create ZIP, Extract ZIP, Chart Maker, YAML/JSON |
 
 ### Pipelines
 

apps/docs/guide/supported-formats.md

@@ -148,7 +148,7 @@ Document processing uses qpdf, LibreOffice, Ghostscript, Pandoc, and WeasyPrint.
 | **Input** | PDF, DOCX, DOC, XLSX, XLS, PPTX, PPT, ODT, ODS, ODP, RTF, TXT, Markdown, HTML, EPUB |
 | **Output** | PDF, PDF/A, DOCX, HTML, EPUB, images (via PDF to Image) |
 
-## Data Formats
+## File Formats
 
 | Type | Formats |
 |------|---------|