feat: add archived column to sessions table and isSunday helper

Made-with: Cursor

backend/database.js

@@ -56,6 +56,13 @@ function initializeDatabase() {
     )
   `);
 
+  // Add archived column if it doesn't exist (for existing databases)
+  try {
+    db.exec(`ALTER TABLE sessions ADD COLUMN archived INTEGER DEFAULT 0`);
+  } catch (err) {
+    // Column already exists, ignore error
+  }
+
   // Session games table
   db.exec(`
     CREATE TABLE IF NOT EXISTS session_games (