tool: biome for formatting

biome.jsonc

@@ -0,0 +1,38 @@
+{
+	"$schema": "https://biomejs.dev/schemas/2.3.14/schema.json",
+	"files": {
+		"includes": [
+			"*.js",
+			"*.ts",
+			"*.json",
+			"*.jsonc",
+			"src/**/*.ts",
+			"src/**/*.svelte",
+			"!src/lib/components/ui/**/*",
+			"!src/worker-configuration.d.ts"
+		]
+	},
+	// https://biomejs.dev/internals/language-support/#linting-html-ish-languages
+	"overrides": [
+		{
+			"includes": ["**/*.svelte", "**/*.astro", "**/*.vue"],
+			"html": {
+				"formatter": {
+					"indentScriptAndStyle": true
+				}
+			},
+			"linter": {
+				"rules": {
+					"style": {
+						"useConst": "off",
+						"useImportType": "off"
+					},
+					"correctness": {
+						"noUnusedVariables": "off",
+						"noUnusedImports": "off"
+					}
+				}
+			}
+		}
+	]
+}