Fix video controls, reaction scroll loss, and PHP warning

[akirk]

Summary

I looked at the open issues and found three that are fixable for the 4.0 release:

• Video controls not visible (Video controls not visible and no way to play video except if activate and disable picture-in-picture #602, Video from Mastodon in Feed - only preview image shown #588): I added the missing controls attribute to <video> tags in the ActivityPub attachment path and the Microformats parser. The detailed video handler already had controls="controls" but the simpler attachment fallback was missing it. I also added the missing </video> closing tag which was causing invalid HTML.

• Page reloads on setting reaction (Friends feed page reloading on setting reaction #589): I replaced window.location.reload() in both reaction handlers with in-place DOM updates. Toggling an existing reaction now updates the count and pressed state directly. Picking a new reaction from the emoji picker either increments an existing button or inserts a new one. This preserves scroll position so you don't lose your place in the feed.

• PHP warning "Undefined array key 'friend'" (Warning when updating a feed #597): I added a ! empty() guard when iterating dashboard widgets, since widget entries may not always have a 'friend' key (e.g. format-only widgets). This matches the pattern already used elsewhere in the same file.

I also looked at the other open issues — #595 is already fixed, #569 is already fixed in the current code, and the rest (#596, #555, #590, #564, #558, #570) are either user-specific config/cron issues or need deeper architectural work.

Closes #602, closes #588, closes #589, closes #597

Test plan

• Add an ActivityPub subscription that posts videos — verify video controls are visible
• Click a reaction emoji on a post — verify the count updates without page reload
• Pick a new reaction from the emoji picker — verify it appears without page reload
• Toggle an existing reaction off — verify it disappears without page reload
• Edit feeds for a subscription with dashboard widgets — verify no PHP warning

WordPress Playground: https://playground.wordpress.net/#{%22steps%22:[{%22step%22:%22installPlugin%22,%22pluginData%22:{%22resource%22:%22git:directory%22,%22url%22:%22https://github.com/akirk/friends%22,%22ref%22:%22fix/issue-fixes-for-4.0%22,%22refType%22:%22branch%22},%22options%22:{%22activate%22:true}}]}

[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.