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>

radio.php

@@ -5,7 +5,7 @@
  * Plugin Name: Radio
  * Plugin URI:  https://icanhelp.ie/radio
  * Description: A small, focused, free radio player for your WordPress admin. 44 SomaFM stations grouped by 10 genres — ambient, electronic, lounge, rock, metal, jazz, world, reggae, holiday, specials. Plays via HTML5 audio; volume + station choice persist per-user.
- * Version:     0.3.1
+ * Version:     0.3.2
  * Requires at least: 5.0
  * Requires PHP: 7.4
  * Author:      David Keane
@@ -20,7 +20,7 @@
 if ( ! defined( 'ABSPATH' ) ) { exit; }
 
 // Plugin coordinates.
-if ( ! defined( 'RADIO_VERSION' ) )   { define( 'RADIO_VERSION',   '0.3.1' ); }
+if ( ! defined( 'RADIO_VERSION' ) )   { define( 'RADIO_VERSION',   '0.3.2' ); }
 if ( ! defined( 'RADIO_FILE' ) )      { define( 'RADIO_FILE',      __FILE__ ); }
 if ( ! defined( 'RADIO_PATH' ) )      { define( 'RADIO_PATH',      plugin_dir_path( __FILE__ ) ); }
 if ( ! defined( 'RADIO_URL' ) )       { define( 'RADIO_URL',       plugin_dir_url( __FILE__ ) ); }