fix: resolve WASM file loading issue for npx execution (closes #31)

- Enhanced database adapter to support multiple WASM file resolution strategies
- Added require.resolve() for reliable package location in npm environments
- Made better-sqlite3 an optional dependency
- Improved error handling with clear messages
- Updated version to 2.7.13
- Updated CHANGELOG and README badges

scripts/test-database-adapter.js

@@ -0,0 +1,38 @@
+#!/usr/bin/env node
+
+const { createDatabaseAdapter } = require('../dist/database/database-adapter');
+const path = require('path');
+
+async function testDatabaseAdapter() {
+  console.log('Testing database adapter initialization...\n');
+  
+  const dbPath = path.join(__dirname, '../data/nodes.db');
+  console.log('Database path:', dbPath);
+  
+  try {
+    console.log('Creating database adapter...');
+    const adapter = await createDatabaseAdapter(dbPath);
+    
+    console.log('\n✅ Database adapter created successfully!');
+    
+    // Test a simple query
+    console.log('\nTesting database query...');
+    const stmt = adapter.prepare('SELECT COUNT(*) as count FROM nodes');
+    const result = stmt.get();
+    console.log(`✅ Database contains ${result.count} nodes`);
+    
+    // Check FTS5 support
+    console.log('\nChecking FTS5 support...');
+    const hasFTS5 = adapter.checkFTS5Support();
+    console.log(`FTS5 support: ${hasFTS5 ? '✅ Available' : '❌ Not available'}`);
+    
+    adapter.close();
+    console.log('\n✅ All tests passed!');
+  } catch (error) {
+    console.error('\n❌ Error:', error.message);
+    console.error('Stack:', error.stack);
+    process.exit(1);
+  }
+}
+
+testDatabaseAdapter();