An OpenThread BR dBus API (#472)

Similar to #457 (and the justification for #457 is actually good!) but
also:
- The full dBus API, not just "what currently the controller needs"
- Not sure who is "the controller", but "a" controller might need other
APIs too
 - We try to expose the full API in all zbus proxies anyway

- Copyright headers in the rs-matter format, not shortened. Why are they
shortened?!?!

- A promise to assess the Gemini code review feedback

Author: ivmarkov

rs-matter/Cargo.toml

@@ -116,7 +116,7 @@ max-btp-sessions-1 = [] # default
 # General
 astro-dnssd = ["os", "dep:astro-dnssd"]
 zeroconf = ["os", "dep:zeroconf"]
-zbus = ["dep:zbus", "os", "futures-lite", "libc", "uuid", "async-channel"]
+zbus = ["dep:zbus", "dep:serde", "os", "futures-lite", "libc", "uuid", "async-channel"]
 bluer = ["dep:bluer", "os"]
 os = ["std", "backtrace", "async-io", "critical-section/std", "embassy-sync/std", "embassy-time/std", "dep:if-addrs"]
 std = ["alloc", "rand"]
@@ -191,6 +191,7 @@ async-compat = { version = "0.2", optional = true, default-features = false }
 
 # OS
 zbus = { version = "5.8", optional = true }
+serde = { version = "1", optional = true, default-features = false, features = ["derive"] }
 async-channel = { version = "2", optional = true }
 uuid = { version = "1", optional = true, features = ["v4"] }
 libc = { version = "0.2", optional = true }

rs-matter/src/utils/zbus_proxies.rs

@@ -1,6 +1,6 @@
 /*
  *
- *    Copyright (c) 2025 Project CHIP Authors
+ *    Copyright (c) 2025-2026 Project CHIP Authors
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -20,5 +20,6 @@
 pub mod avahi;
 pub mod bluez;
 pub mod nm;
+pub mod openthread;
 pub mod resolve;
 pub mod wpa_supp;

rs-matter/src/utils/zbus_proxies/openthread.rs

@@ -0,0 +1,27 @@
+/*
+ *
+ *    Copyright (c) 2026 Project CHIP Authors
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+//! zbus proxies for OpenThread Border Router (`otbr-agent`).
+//!
+//! OTBR exposes a per-Thread-interface D-Bus service named
+//! `io.openthread.BorderRouter.<ifname>` (typically `io.openthread.BorderRouter.wpan0`)
+//! under the well-known object path `/io/openthread/BorderRouter/<ifname>`.
+//!
+//! The full interface is defined in `openthread/src/posix/platform/dbus/` and
+//! documented at <https://github.com/openthread/ot-br-posix>.
+
+pub mod border_router;