Feat: page Play — backgroundColor, playLink, play-icon + fix slug jouer

- Renommage dossier content 3_play → 3_jouer (slug /jouer)
- Champ backgroundColor (code-editor) dans game.yml + exposé en API
- playLinks simplifié en champ url simple → playLink dans l'API
- Variable CSS --background-color sur la section .play
- Bouton "Jouer" avec icône play-icon (SVG data URI dans buttons.css)
- Plugin sylvainjule/code-editor ajouté via composer

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

vendor/composer/installed.json

@@ -748,6 +748,47 @@
             },
             "install-path": "../psr/log"
         },
+        {
+            "name": "sylvainjule/code-editor",
+            "version": "1.1.0",
+            "version_normalized": "1.1.0.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/sylvainjule/kirby-code-editor.git",
+                "reference": "adbc2c8a728994cc57ea72a7f8628f27d202b8df"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/sylvainjule/kirby-code-editor/zipball/adbc2c8a728994cc57ea72a7f8628f27d202b8df",
+                "reference": "adbc2c8a728994cc57ea72a7f8628f27d202b8df",
+                "shasum": ""
+            },
+            "require": {
+                "getkirby/composer-installer": "^1.2"
+            },
+            "time": "2025-08-04T17:32:08+00:00",
+            "type": "kirby-plugin",
+            "extra": {
+                "installer-name": "code-editor"
+            },
+            "installation-source": "dist",
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Sylvain Julé",
+                    "email": "contact@sylvain-jule.fr"
+                }
+            ],
+            "description": "Code editor field for Kirby 3, 4 and 5",
+            "support": {
+                "issues": "https://github.com/sylvainjule/kirby-code-editor/issues",
+                "source": "https://github.com/sylvainjule/kirby-code-editor/tree/1.1.0"
+            },
+            "install-path": "../../site/plugins/code-editor"
+        },
         {
             "name": "symfony/deprecation-contracts",
             "version": "v3.6.0",