refactor: migrate player_positions table to add label column for enhanced data tracking

server/database.js

@@ -160,10 +160,22 @@ export function initializeDatabase() {
       x INTEGER NOT NULL,
       y INTEGER NOT NULL,
       z INTEGER NOT NULL,
+      label TEXT,
       updated_at INTEGER NOT NULL
     )
   `);
 
+  // Migrate player_positions table to add label column if missing
+  try {
+    const tableInfo = db.prepare("PRAGMA table_info(player_positions)").all();
+    const columns = tableInfo.map(c => c.name);
+    if (!columns.includes('label')) {
+      db.exec('ALTER TABLE player_positions ADD COLUMN label TEXT');
+    }
+  } catch (e) {
+    // Ignore migration errors
+  }
+
   // Chunk analysis table (ore density per chunk)
   db.exec(`
     CREATE TABLE IF NOT EXISTS chunks (