Plugin Directory: Add unit tests for Email\Base::plugin_title()

[dd32]

Adds unit tests for the plugin_title() helper method introduced in #606.

Summary

• 14 test cases covering realistic entity scenarios observed in the plugin directory database
• Uses reflection to bypass the Base constructor (which requires DB access)
• Uses an anonymous subclass to expose the protected method

Test coverage

Based on real plugin titles found in the DB:

• Registered trademark (®), trademark (™), copyright (©), degree (°)
• Accented characters (ç, ã, é, etc.)
• Numeric entities (★ stars)
• Hex numeric entities (🏦 building emoji)
• HTML5-only entities (')
• Non-breaking space ( )
• Already-decoded UTF-8 characters (unchanged pass-through)
• Empty string, plain text, quote entities

Test plan

• Verify all tests pass in CI (WP: Plugin Directory job)

🤖 Generated with Claude Code

[github-actions]

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Props dd32.

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