Port Brave Sync server to Rust

Use SQLite for persistence and generate Rust protobuf bindings at build time.

Add Docker image support for containerized deployment.

Co-Authored-By: codex <[email protected]>

schema/protobuf/sync_pb/persisted_entity_data.proto

@@ -0,0 +1,28 @@
+// Copyright 2018 The Chromium Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+syntax = "proto2";
+
+option go_package = "./sync_pb";
+
+option java_multiple_files = true;
+option java_package = "org.chromium.components.sync.protocol";
+
+option optimize_for = LITE_RUNTIME;
+
+package sync_pb;
+
+import "entity_specifics.proto";
+
+// Sync proto to store entity data similar to what the legacy Directory used
+// to store, used to persist data locally and never sent through the wire.
+//
+// Because it's conceptually similar to SyncEntity (actual protocol) and it's
+// unclear how big this'll grow, we've kept compatibility with SyncEntity by
+// using the same field numbers.
+message PersistedEntityData {
+  // See corresponding fields in SyncEntity for details.
+  optional string name = 8;
+  optional EntitySpecifics specifics = 21;
+}