feat: add OCR language extension configuration and documentation

- Introduced `compose.ocr-languages.yml` for installing additional Tesseract OCR language packs during container startup.
- Updated documentation to include new OCR language extension options and usage scenarios.
- Enhanced existing documentation with references to the new OCR language extension guide.
- Improved test coverage for the deark converter and formats, ensuring accurate format handling and error management.
- Refactored code to streamline file system operations and improve readability.

src/converters/deark.ts

@@ -1,5 +1,5 @@
 import { execFile as execFileOriginal } from "node:child_process";
-import { mkdirSync, existsSync, readdirSync, unlinkSync, rmdirSync, statSync } from "node:fs";
+import { mkdirSync, existsSync, readdirSync, unlinkSync, rmdirSync } from "node:fs";
 import { join, basename, dirname } from "node:path";
 import { ExecFileFn } from "./types";