feat: add .mustacheignore pattern support with glob matching

- Load ignore patterns from .mustacheignore file
- Support simple paths, directory prefixes, and glob patterns
- Add comprehensive test coverage for pattern matching
- Update scanDirectory to respect ignore patterns

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <[email protected]>

Author: ashleyshaw

scripts/utils/__tests__/scan.test.js

@@ -0,0 +1,53 @@
+/**
+ * Tests for scan utilities
+ */
+const fs = require('fs');
+const path = require('path');
+const {
+	loadIgnorePatterns,
+	shouldIgnorePath,
+} = require('../scan');
+
+describe('loadIgnorePatterns', () => {
+	const tempDir = path.join(__dirname, 'temp-ignore-test');
+	const ignorePath = path.join(tempDir, '.mustacheignore');
+
+	beforeEach(() => {
+		if (!fs.existsSync(tempDir)) {
+			fs.mkdirSync(tempDir, { recursive: true });
+		}
+	});
+
+	afterEach(() => {
+		if (fs.existsSync(ignorePath)) {
+			fs.unlinkSync(ignorePath);
+		}
+		if (fs.existsSync(tempDir)) {
+			fs.rmdirSync(tempDir);
+		}
+	});
+
+	test('returns empty array when .mustacheignore does not exist', () => {
+		const patterns = loadIgnorePatterns(tempDir);
+		expect(patterns).toEqual([]);
+	});
+
+	test('loads patterns from .mustacheignore file', () => {
+		fs.writeFileSync(ignorePath, 'node_modules/\nbuild/\n# comment\n\ndocs/');
+		const patterns = loadIgnorePatterns(tempDir);
+		expect(patterns).toEqual(['node_modules/', 'build/', 'docs/']);
+	});
+
+	test('shouldIgnorePath matches simple patterns', () => {
+		const patterns = ['node_modules/', 'build/'];
+		expect(shouldIgnorePath('node_modules/package', patterns)).toBe(true);
+		expect(shouldIgnorePath('src/index.js', patterns)).toBe(false);
+	});
+
+	test('shouldIgnorePath matches glob patterns', () => {
+		const patterns = ['**/*.test.js', 'src/experimental/**'];
+		expect(shouldIgnorePath('src/utils/scan.test.js', patterns)).toBe(true);
+		expect(shouldIgnorePath('src/experimental/feature.js', patterns)).toBe(true);
+		expect(shouldIgnorePath('src/utils/scan.js', patterns)).toBe(false);
+	});
+});