feat(scripts): enhance translation progress tool with CLI flags, TOML management, and CI-friendly output (#4801)

# Description of Changes

- **What was changed**
- Refactored `scripts/counter_translation.py` into a more modular CLI
tool.
  - Added argument parsing with new flags:
    - `--lang/-l` to check a single `messages_*.properties` file.
- `--show-percentage/-sp` to print **only** the numeric percentage
(useful for CI).
- `--show-missing-keys/-smk` to list untranslated keys for a single
language.
- Introduced `main()` entrypoint and helper `_lang_from_path()` for
robust language code extraction.
  - Improved comparison logic:
    - Skips header lines, trims values, and tolerates BOM.
    - Treats `en_GB`/`en_US` as 100% translated.
- Tracks and reports missing keys; removes keys from ignore list once
translated.
  - Hardened TOML handling:
- Automatically creates/updates `scripts/ignore_translation.toml` when
absent.
    - `convert_to_multiline()` normalizes/sorts arrays for stable diffs.
  - README integration:
    - `write_readme()` updates language badges from computed progress.
- Added type hints, richer docstrings, usage examples, and clearer
console messages.
  - Deduplicates language results and sorts by percentage (desc).
  - Uses consistent UTF-8 and newline handling.

- **Why the change was made**
- Make translation tracking **automation-ready** (CI pipelines can
consume a single number).
- Reduce manual maintenance of ignore lists and improve
**deterministic** formatting for clean diffs.
- Provide better **developer UX** with explicit flags and actionable
diagnostics (missing keys).
- Increase correctness and maintainability via structured code, typing,
and clear responsibilities.


---

## Checklist

### General

- [x] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [x] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [x] I have performed a self-review of my own code
- [x] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.

docs/counter_translation.md

@@ -0,0 +1,64 @@
+# `counter_translation.py`
+
+## Overview
+
+The script [`scripts/counter_translation.py`](../scripts/counter_translation.py) checks the translation progress of the property files in the directory `app/core/src/main/resources/`.
+It compares each `messages_*.properties` file with the English reference file `messages_en_GB.properties` and calculates a percentage of completion for each language.
+
+In addition to console output, the script automatically updates the progress badges in the project’s `README.md` and maintains the configuration file [`scripts/ignore_translation.toml`](../scripts/ignore_translation.toml), which lists translation keys to be ignored for each language.
+
+## Requirements
+
+- Python 3.10 or newer (requires `tomlkit`).
+- Must be executed **from the project root directory** so all relative paths are resolved correctly.
+- Write permissions for `README.md` and `scripts/ignore_translation.toml`.
+
+## Default usage
+
+```bash
+python scripts/counter_translation.py
+```
+
+This command:
+
+1. scans `app/core/src/main/resources/` for all `messages_*.properties` files,
+2. calculates the translation progress for each file,
+3. updates the badges in `README.md`,
+4. reformats `scripts/ignore_translation.toml` (sorted, multi-line arrays).
+
+## Check a single language
+
+```bash
+python scripts/counter_translation.py --lang messages_fr_FR.properties
+```
+
+- The specified file can be given as a relative (to the resources folder) or absolute path.
+- The result is printed to the console (e.g. `fr_FR: 87% translated`).
+- With `--show-missing-keys`, all untranslated keys are listed as well.
+
+## Output only the percentage
+
+For scripts or CI pipelines, the output can be reduced to just the percentage value:
+
+```bash
+python scripts/counter_translation.py --lang messages_fr_FR.properties --show-percentage
+```
+
+The console will then only print `87` (without the percent symbol or any extra text).
+
+## Handling `ignore_translation.toml`
+
+- If a language section is missing, the script creates it automatically.
+- Entries in `ignore` are alphabetically sorted and written as multi-line arrays.
+- By default, `language.direction` is ignored. If that key is later translated, the script automatically removes it from the ignore list.
+
+## Integration in Pull Requests
+
+Whenever translations are updated, this script should be executed.
+The updated badges and the modified `ignore_translation.toml` should be committed together with the changed `messages_*.properties` files.
+
+## Troubleshooting
+
+- **File not found**: Check the path or use `--lang` with an absolute path.
+- **Line error**: The script reports the specific line in both files—this usually means a missing `=` or an unmatched line.
+- **Incorrect percentages in README**: Make sure the script was run from the project root and that write permissions are available.