Mastodon theme: fix search, add cmd-k, style messages

[akirk]

Summary

• Fix search returning all WP users: User_Query::search(), all_subscriptions(), and starred_friends_subscriptions() were using new self(array('number' => 0)) which ran a WP_User_Query with no role filter, returning all WordPress users alongside virtual subscriptions. Changed to array('include' => array(0)) to suppress the parent query.
• Add cmd-k/ctrl-k shortcut to focus the search input in the Mastodon theme, matching the main theme behavior. Escape blurs it. Added to the ? help overlay.
• Fix search autocomplete styling: Override spectre CSS display: flex and gap: 10px on .menu-item a that broke inline <mark> highlighting (text appeared spaced out). Fix hover/focus artifacts from spectre's padding/margin/background rules. Fix search input resizing during loading spinner.
• Style messages for Mastodon theme: Conversation list, message bubbles, reply form, and unread indicators now match the Mastodon visual language.

Changelog

• Automatically create a changelog entry from the details below

Type

• Fixed

Message

Fix Mastodon theme search autocomplete styling and prevent User_Query from returning non-subscription WordPress users.

Test plan

• Search for a subscription in the Mastodon theme — only subscriptions should appear, no admin users
• Press cmd-k (Mac) or ctrl-k — search input should focus
• Press Escape while search is focused — should blur
• Type a query — autocomplete results should show names with highlighted matches inline (no extra spacing)
• Arrow-down through results — focus highlight should be subtle purple, no blue outlines
• Search input should not resize while loading spinner is active
• Visit a friend's page with messages — messages should be styled in the Mastodon theme

[github-actions]

Test this PR in WordPress Playground

You can test this pull request directly in WordPress Playground:

Launch WordPress Playground

This will install and activate the plugin with the changes from this PR.