Add Nix flake for mciasctl and mciasgrpcctl

Vendor dependencies and expose control program binaries via
nix build. Uses nixpkgs-unstable for Go 1.26 support.

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

vendor/modernc.org/sqlite/lib/hooks.go

@@ -0,0 +1,20 @@
+// Copyright 2019 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.
+
+//go:build !(linux && arm64)
+
+package sqlite3
+
+import (
+	"modernc.org/libc"
+)
+
+// Format and write a message to the log if logging is enabled.
+func X__ccgo_sqlite3_log(t *libc.TLS, iErrCode int32, zFormat uintptr, va uintptr) { /* sqlite3.c:29405:17: */
+	libc.X__ccgo_sqlite3_log(t, iErrCode, zFormat, va)
+}
+
+func PatchIssue199() {
+	// nop
+}