fix(0.3.2): play-button glyph baseline — drop dashicon for Unicode ▶ / ‖

The dashicon used for the play/pause icon was rendering visibly below
the button text — dashicon font metrics sit the glyph low inside its
own box, so even with `inline-flex` centering the symbol looked like
it was on a separate row from the word "Play".

Swap dashicons-controls-play / dashicons-controls-pause for plain
Unicode glyphs (▶ / ‖) which render on the text baseline like any
other character. Flex container changed to align-items: baseline.
font-variant-emoji: text on the glyph span to keep platforms that
might otherwise pick up an emoji variant of ▶ as monochrome text.

Files: radio.php (version), inc/admin-page.php +
inc/dashboard-widget.php (dashicon span → glyph span),
assets/css/radio.css (drop dashicon-sizing rule, add
.radio-player__play-glyph, baseline alignment),
assets/js/radio.js (setPlayIcon swaps glyph textContent instead of
dashicon className), inc/about.php (history entry).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

assets/js/radio.js

@@ -68,11 +68,13 @@
         });
     }
 
-    /** Update play/pause button icon + label to reflect current audio state. */
+    /** Update play/pause button glyph + label to reflect current audio state.
+     *  v0.3.2: switched from .dashicons to a Unicode glyph so the symbol sits
+     *  on the text baseline instead of below it. */
     function setPlayIcon(btn, playing) {
-        var icon  = btn.querySelector('.dashicons');
+        var glyph = btn.querySelector('[data-radio-play-glyph]');
         var label = btn.querySelector('[data-radio-play-label]');
-        if (icon)  { icon.className  = 'dashicons ' + (playing ? 'dashicons-controls-pause' : 'dashicons-controls-play'); }
+        if (glyph) { glyph.textContent = playing ? '‖' : '▶'; } // ‖ or ▶
         if (label) { label.textContent = playing ? (cfg.strings.pause || 'Pause') : (cfg.strings.play || 'Play'); }
         btn.setAttribute('title', playing ? (cfg.strings.pause || 'Pause') : (cfg.strings.play || 'Play'));
     }