Add Nix flake for mcproxyctl

Vendor dependencies and expose mcproxyctl binary via nix build.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

vendor/modernc.org/sqlite/result.go

@@ -0,0 +1,42 @@
+// Copyright 2025 The Sqlite Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package sqlite // import "modernc.org/sqlite"
+
+type result struct {
+	lastInsertID int64
+	rowsAffected int
+}
+
+func newResult(c *conn) (_ *result, err error) {
+	r := &result{}
+	if r.rowsAffected, err = c.changes(); err != nil {
+		return nil, err
+	}
+
+	if r.lastInsertID, err = c.lastInsertRowID(); err != nil {
+		return nil, err
+	}
+
+	return r, nil
+}
+
+// LastInsertId returns the database's auto-generated ID after, for example, an
+// INSERT into a table with primary key.
+func (r *result) LastInsertId() (int64, error) {
+	if r == nil {
+		return 0, nil
+	}
+
+	return r.lastInsertID, nil
+}
+
+// RowsAffected returns the number of rows affected by the query.
+func (r *result) RowsAffected() (int64, error) {
+	if r == nil {
+		return 0, nil
+	}
+
+	return int64(r.rowsAffected), nil
+}