Fix: Add database migration for new columns

ALTER TABLE guild_settings adds missing columns:
- welcome_message, goodbye_message
- log_channel, log_events

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/structures/Database.ts

@@ -103,6 +103,23 @@ export class DB {
             )
         `).run();
 
+        // Migration: Add missing columns to existing guild_settings
+        const columns = db.prepare("PRAGMA table_info(guild_settings)").all() as any[];
+        const columnNames = columns.map((c: any) => c.name);
+
+        if (!columnNames.includes('welcome_message')) {
+            db.prepare('ALTER TABLE guild_settings ADD COLUMN welcome_message TEXT').run();
+        }
+        if (!columnNames.includes('goodbye_message')) {
+            db.prepare('ALTER TABLE guild_settings ADD COLUMN goodbye_message TEXT').run();
+        }
+        if (!columnNames.includes('log_channel')) {
+            db.prepare('ALTER TABLE guild_settings ADD COLUMN log_channel TEXT').run();
+        }
+        if (!columnNames.includes('log_events')) {
+            db.prepare('ALTER TABLE guild_settings ADD COLUMN log_events TEXT DEFAULT \'messages,roles,nicks,channels,warns,mutes,kicks,bans\'').run();
+        }
+
         console.log('[DATABASE] Initialization complete.');
     }