feat: add SQLite database and projects table schema

- Install better-sqlite3 package for persistent storage
- Create database service with projects table schema
- Add indexes on deletedAt and name for efficient queries
- Support soft-delete with deletedAt timestamp
- Export database instance for use in server.js

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

services/database.js

@@ -0,0 +1,69 @@
+const Database = require('better-sqlite3');
+const path = require('path');
+
+/**
+ * Initialize SQLite database with projects schema
+ */
+function initializeDatabase() {
+  // Database file in project root
+  const dbPath = path.join(__dirname, '..', 'database.sqlite');
+
+  // Initialize database connection
+  const db = new Database(dbPath);
+
+  // Enable WAL mode for better concurrency
+  db.pragma('journal_mode = WAL');
+
+  // Create projects table
+  db.exec(`
+    CREATE TABLE IF NOT EXISTS projects (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      name TEXT NOT NULL UNIQUE,
+      description TEXT,
+      icon TEXT DEFAULT '📁',
+      color TEXT DEFAULT '#4a9eff',
+      path TEXT NOT NULL,
+      createdAt TEXT NOT NULL,
+      lastActivity TEXT NOT NULL,
+      deletedAt TEXT NULL
+    )
+  `);
+
+  // Create index on deletedAt for efficient soft-delete queries
+  db.exec(`
+    CREATE INDEX IF NOT EXISTS idx_projects_deletedAt ON projects(deletedAt)
+  `);
+
+  // Create index on name for efficient name lookups
+  db.exec(`
+    CREATE INDEX IF NOT EXISTS idx_projects_name ON projects(name)
+  `);
+
+  return db;
+}
+
+/**
+ * Initialize database with requireAuth check
+ */
+let dbInstance = null;
+
+function getDatabase() {
+  if (!dbInstance) {
+    try {
+      dbInstance = initializeDatabase();
+      console.log('Database initialized successfully');
+    } catch (error) {
+      console.error('Failed to initialize database:', error);
+      throw error;
+    }
+  }
+  return dbInstance;
+}
+
+// Initialize database immediately
+const db = getDatabase();
+
+module.exports = {
+  db,
+  getDatabase
+};