milestone 2 complete

internal/core/transaction.go

@@ -155,6 +155,25 @@ func (t *Transaction) Rollback(entryID uint64) error {
 	return nil
 }
 
+// Commit captures the final state and writes to oplog
+func (t *Transaction) Commit(operation, description string) error {
+	// Capture state_after
+	stateAfter, err := t.stateCapture.CaptureState()
+	if err != nil {
+		return fmt.Errorf("failed to capture state: %w", err)
+	}
+
+	// Create oplog entry
+	entry := models.NewOplogEntry(0, operation, description, nil, stateAfter)
+
+	// Write to oplog
+	if err := t.oplogWriter.AppendEntry(entry); err != nil {
+		return fmt.Errorf("failed to write to oplog: %w", err)
+	}
+
+	return t.Close()
+}
+
 // Helper function to execute a transaction on a repository
 func ExecuteWithTransaction(repo *OnyxRepository, operation, description string, fn func() error) error {
 	txn, err := NewTransaction(repo)