Add Persian locale

[zalaghi]

Why

This adds a complete Persian (Farsi, fa-IR) localization for the current develop branch of Nginx Proxy Manager.

The translation is intended for Persian-speaking users and has been reviewed for Nginx/networking terminology rather than translated literally. Technical terms such as Proxy Host, Upstream, Location, DNS Challenge, HSTS, WebSocket, and SSL/TLS are translated contextually while retaining the original English term where that improves clarity.

Persian is a right-to-left language, so this change also adds RTL document direction, loads Tabler's RTL stylesheet when Persian is active, and enables RTL rendering for toast notifications.

This contribution builds on and credits the earlier Persian localization work in #5582. That PR is currently behind develop, is not mergeable, and is missing newer locale keys, so this PR refreshes the work against the current codebase and substantially reviews the terminology and help text.

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Code refactoring
• API changes
• Performance improvement
• Test addition or update

AI Usage

• [] AI was used to write this
• [] AI was used to review this

What changed

• Added Persian (fa-IR) to the language selector.
• Added all 261 current frontend locale keys.
• Added Persian HelpDoc translations for Access Lists, Certificates, 404 Hosts, Proxy Hosts, Redirection Hosts, and Streams.
• Added Persian/RTL flag handling.
• Sets lang and dir on the document for RTL locales.
• Loads Tabler's RTL stylesheet for Persian.
• Enables RTL layout for toast notifications.
• Added Persian to check-locales.cjs.

Validation

• Locale key parity checked against the current en.json: 261/261 keys.
• Required interpolation placeholders were checked for the translated messages.
• Branch is based directly on current develop commit 568c10594517b999dbb2240d9f7a6014b1c4bb2a.
• No unrelated commits or files are included.

CI/build results are intentionally not claimed here until GitHub Actions has run on this pull request.

[nginxproxymanagerci]

Docker Image for build 1 is available on DockerHub:

nginxproxymanager/nginx-proxy-manager-dev:pr-5869

Note

Ensure you backup your NPM instance before testing this image! Especially if there are database changes.
This is a different docker image namespace than the official image.

Warning

Changes and additions to DNS Providers require verification by at least 2 members of the community!