Include readme-translations in MANIFEST

Add a recursive-include rule for the readme-translations directory to MANIFEST.in so translated README files are included in source distributions (sdist) and packaged with releases.

Bump version to 5.1.0

Update package version from 5.0.10b to 5.1.0 in pyproject.toml and ytsage/__init__.py to prepare for the 5.1.0 release.

Bump version to 5.0.3

Update package version from 5.0.2b to 5.0.3 in pyproject.toml and ytsage/__init__.py to prepare the 5.0.3 release.

Bump version to 5.0.3

Update package version from 5.0.2b to 5.0.3 in pyproject.toml and ytsage/__init__.py to prepare the 5.0.3 release.

Bump version to 5.0.3

Update package version from 5.0.2b to 5.0.3 in pyproject.toml and ytsage/__init__.py to prepare the 5.0.3 release.

Bump version to 5.0.3

Update package version from 5.0.2b to 5.0.3 in pyproject.toml and ytsage/__init__.py to prepare the 5.0.3 release.

Bump version to 5.0.3

Update package version from 5.0.2b to 5.0.3 in pyproject.toml and ytsage/__init__.py to prepare the 5.0.3 release.

Bump version to 5.0.3

Update package version from 5.0.2b to 5.0.3 in pyproject.toml and ytsage/__init__.py to prepare the 5.0.3 release.

Add UI tab labels to translation files

Add "tab_general", "tab_format", and "tab_file" entries to multiple ytsage/languages/*.json files to provide localized labels for the UI tabs (General, Format, File). Also include a minor formatting/newline fix in en.json.

Reorganize README sections and update wording

Rename and restructure the options section: 'Advanced Options' becomes 'Media and Download Options', and new sections 'Output and File Settings', 'Access and Network', and 'Tools and Maintenance' are added. Clarify and reword items (subtitle embedding/merge, save thumbnail/description, trim video, speed limiter, proxy, cookie extraction), and consolidate updater/FFmpeg/yt-dlp/Deno detection and history/tooling notes. Documentation-only cleanup to improve clarity and discoverability of features.