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>

site/plugins/code-editor/package.json

@@ -0,0 +1,30 @@
+{
+	"name": "kirby-code-editor",
+	"version": "1.0.3",
+	"description": "Code editor field for Kirby 3 and 4",
+	"main": "index.js",
+	"author": "Kirby Community",
+	"license": "MIT",
+	"repository": {
+		"type": "git",
+		"url": "git@github.com:sylvainjule/kirby-code-editor.git"
+	},
+	"scripts": {
+		"dev": "kirbyup src/index.js --watch",
+		"build": "kirbyup src/index.js",
+		"lint": "eslint \"src/**/*.{js,vue}\"",
+		"lint:fix": "npm run lint -- --fix",
+		"format": "prettier --write \"src/**/*.{css,js,vue}\"",
+		"prepare": "node src/node/patchVuePrismEditor.mjs"
+	},
+	"devDependencies": {
+		"consola": "^3.4.2",
+		"eslint": "^9.27.0",
+		"eslint-config-prettier": "^10.1.5",
+		"eslint-plugin-vue": "^9.33.0",
+		"kirbyup": "^3.3.0",
+		"prettier": "^3.5.3",
+		"prismjs": "^1.30.0",
+		"vue-prism-editor": "^1.3.0"
+	}
+}