Various fixes and improvements

[dsevillamartin]

Changes proposed in this pull request:

• fix: ignore empty filter lines to avoid matching everything (fixes Empty line in words list matches every post #51)
• allow email translations (fixes Cannot use email feature in multi-language environment #50)
• stop newlines turning into usernames by introducing %USERNAME% placeholder (fixes Newlines in email are replaced with the username #49)

Reviewers should focus on:
Migration I made to catch slight changes to template (case sensitivity, new lines) just to avoid needing people to clear manually as much as possible. It's kind of scuffed but should work as it matches line for line.

Screenshot

Confirmed

• Frontend changes: tested on a local Flarum installation.
• Backend changes: tests are green (run composer test).

Required changes:

• Related Flarum core extension PR's: (Omit this section if irrelevant)

[Copilot]

Pull Request Overview

This PR implements several fixes and improvements to the filter extension, including empty filter handling, email translation support, and username placeholder functionality.

• Fixes empty filter lines that would match everything by filtering out empty strings
• Adds support for email translations by removing hardcoded default email templates and introducing a %USERNAME% placeholder
• Updates dependencies and modernizes PHP code with typed properties and return types

Reviewed Changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/Listener/CheckPost.php	Modernizes PHP syntax with typed properties and fixes username handling in emails
src/CensorGenerator.php	Refactors leet speak replacements and adds filtering for empty filter strings
resources/locale/en.yml	Updates email template with %USERNAME% placeholder and adds translation help text
migrations/2025_08_29_000000_delete_default_email_template.php	Adds migration to remove old hardcoded email templates for translation support
js/src/admin/components/FilterSettingsPage.tsx	Adds help text for email translation functionality
js/package.json	Updates JavaScript dependencies to newer versions

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