expand magic byte detection for common file formats

Add detection for:
- Images: BMP, TIFF, ICO
- Video: MP4, WebM, FLV, Matroska
- Audio: MP3, FLAC, OGG
- Documents: MS Office OLE (DOC/XLS/PPT)
- Executables: PE (EXE/DLL), ELF, Mach-O, WASM
- Archives: BZIP2, XZ, ZSTD, LZ4, 7z, RAR
- Data: SQLite

This improves REQUIRE_BINARY enforcement by detecting more
recognizable formats that should be encrypted before upload.

documentation/api.md

@@ -464,13 +464,16 @@ X-SSL-Client-SHA1: a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2
    | Images | PNG, JPEG, GIF, WebP, BMP, TIFF, ICO |
    | Video | MP4, WebM, FLV, Matroska |
    | Audio | MP3, FLAC, OGG |
-   - GZIP: `\x1f\x8b`
-
-2. **Explicit Content-Type header** (if not generic)
-
-3. **UTF-8 detection** (falls back to `text/plain`)
-
-4. **Binary fallback** (`application/octet-stream`)
+   | Documents | PDF, MS Office (DOC/XLS/PPT), ZIP-based (DOCX/XLSX/ODT) |
+   | Executables | EXE/DLL (PE), ELF (Linux), Mach-O (macOS), WASM |
+   | Archives | ZIP, GZIP, BZIP2, XZ, ZSTD, LZ4, 7z, RAR |
+   | Data | SQLite |
+
+2. **Explicit Content-Type header** (if not generic)
+
+3. **UTF-8 detection** (falls back to `text/plain`)
+
+4. **Binary fallback** (`application/octet-stream`)
 
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