refactor(setup): consolidate prettier config and streamline CI

- Replace scattered .prettierignore files with a single root config
- Add scripts/ci.js to orchestrate lint, format, typecheck, commitlint, and build
- Simplify ci.yml to use ci.js and npm ci
- Apply prettier formatting to docs, locales, and HTML files

scripts/ci.js

@@ -0,0 +1,55 @@
+#!/usr/bin/env node
+/**
+ * CI check script. Run locally before commit or in GitHub Actions.
+ *
+ * Usage:
+ *   node scripts/ci.js            # run all checks
+ *   node scripts/ci.js --no-build # skip build step
+ */
+import chalk from 'chalk'
+import { execSync } from 'child_process'
+
+import { parallelTask } from './parallel-task.js'
+
+const args = new Set(process.argv.slice(2))
+const skipBuild = args.has('--no-build')
+
+function run(label, command) {
+	console.log(chalk.bgBlue.white.bold(` ▸ ${label} `))
+	execSync(command, { stdio: 'inherit' })
+}
+
+function isMainBranch() {
+	if (process.env.GITHUB_REF) return process.env.GITHUB_REF === 'refs/heads/main'
+	try {
+		return execSync('git rev-parse --abbrev-ref HEAD', { encoding: 'utf-8' }).trim() === 'main'
+	} catch {
+		return true
+	}
+}
+
+// 1. Commitlint — skip on main
+if (isMainBranch()) {
+	console.log(chalk.dim(' ▸ commitlint (skipped on main)'))
+} else {
+	const from = execSync('git merge-base origin/main HEAD', { encoding: 'utf-8' }).trim()
+	run('commitlint', `npx commitlint --from ${from} --to HEAD`)
+}
+
+// 2. Lint + Format + Typecheck in parallel
+console.log(chalk.bgBlue.white.bold(' ▸ lint + format + typecheck '))
+await parallelTask(
+	[
+		{ label: 'lint', command: 'npm run lint' },
+		{ label: 'format', command: 'npx prettier --check .' },
+		{ label: 'typecheck', command: 'npm run typecheck' },
+	],
+	{ timeoutMs: 120_000 }
+)
+
+// 3. Build
+if (skipBuild) {
+	console.log(chalk.dim(' ▸ build (skipped)'))
+} else {
+	run('build', 'npm run build')
+}