feat: add CreateLocalDeployment IPC support (C + C++ + Rust)

Add CreateLocalDeployment operation to the C, C++, and Rust SDK, enabling
components to trigger local deployments via IPC without shelling out
to greengrass-cli.

Changes since initial review:
- Full schema: GgCreateLocalDeploymentArgs struct exposes all 6 fields
  (componentToConfiguration, rootComponentVersionsToAdd,
  rootComponentsToRemove, recipeDirectoryPath, artifactsDirectoryPath,
  failureHandlingPolicy)
- C++ wrapper: Client::create_local_deployment() added
- README: CreateLocalDeployment section with C/C++/Rust examples
- Mock packets: renamed ACCEPTED_HEADERS to RESPONSE_HEADERS per real
  IPC traces captured via GGLite-IPC-EventStream-Sniffer against
  Classic Nucleus v2.17.0
- Doc comments: clarified Classic vs Lite behavior (Lite has native
  support via ggdeploymentd, no Cli dep or ACL required)

Testing:
- nix flake check: 17/17 checks pass (formatting, namespacing,
  spelling, IWYU, C tests 45/45, Rust tests 28/28, cross-compile
  x86_64 + aarch64 + armv7l)
- Integration: cache-proxy-bridge/server/common all compile and pass
  172 tests with the updated SDK vendored in

Author: Mitchell

README.md

@@ -31,6 +31,77 @@ The following Greengrass v2 IPC operations are currently supported by this SDK:
 - [UpdateThingShadow](https://docs.aws.amazon.com/greengrass/v2/developerguide/ipc-local-shadows.html#ipc-operation-updatethingshadow)
 - [DeleteThingShadow](https://docs.aws.amazon.com/greengrass/v2/developerguide/ipc-local-shadows.html#ipc-operation-deletethingshadow)
 - [ListNamedShadowsForThing](https://docs.aws.amazon.com/greengrass/v2/developerguide/ipc-local-shadows.html#ipc-operation-listnamedshadowsforthing)
+- [CreateLocalDeployment](https://docs.aws.amazon.com/greengrass/v2/developerguide/ipc-local-deployments-components.html#ipc-operation-createlocaldeployment)
+
+## CreateLocalDeployment
+
+Creates a local deployment to apply component configuration changes or
+add/remove components on the device.
+
+> **Greengrass Classic vs Lite:** On Greengrass Classic, this operation requires
+> a dependency on `aws.greengrass.Cli` and an appropriate ACL policy in your
+> recipe. On Greengrass Nucleus Lite, CreateLocalDeployment is natively
+> supported — no additional dependency or ACL is needed.
+
+### GgCreateLocalDeploymentArgs Fields
+
+| Field                            | Type              | Description                                                 |
+| -------------------------------- | ----------------- | ----------------------------------------------------------- |
+| `component_to_configuration`     | `GgObject` (map)  | Map of component names to configuration objects to merge    |
+| `root_component_versions_to_add` | `GgObject` (map)  | Map of component names to version strings to add            |
+| `root_components_to_remove`      | `GgObject` (list) | List of component names to remove                           |
+| `recipe_directory_path`          | `GgBuffer`        | Path to directory containing component recipes              |
+| `artifacts_directory_path`       | `GgBuffer`        | Path to directory containing component artifacts            |
+| `failure_handling_policy`        | `GgBuffer`        | Failure handling policy (e.g. `"ROLLBACK"`, `"DO_NOTHING"`) |
+
+### C Example
+
+```c
+#include "ggipc.h"
+
+GgCreateLocalDeploymentArgs args = {0};
+// Set component configuration merge
+args.component_to_configuration = my_config_map;
+
+uint8_t id_mem[64];
+GgBuffer deployment_id = {0};
+
+GgError err = ggipc_create_local_deployment(
+    &args,
+    (GgBuffer){.data = id_mem, .len = sizeof(id_mem)},
+    &deployment_id
+);
+```
+
+### C++ Example
+
+```cpp
+#include "gg_ipc/client.hpp"
+
+GgCreateLocalDeploymentArgs args{};
+args.component_to_configuration = my_config_map;
+
+std::array<std::byte, 64> id_mem;
+std::string_view deployment_id;
+
+auto err = client.create_local_deployment(args, id_mem, &deployment_id);
+```
+
+### Rust Example
+
+```rust
+use aws_greengrass_component_sdk::Sdk;
+use std::mem::MaybeUninit;
+
+let mut id_mem = [MaybeUninit::uninit(); 64];
+let deployment_id = sdk.create_local_deployment(
+    config_map,
+    &mut id_mem,
+)?;
+```
+
+> **Note:** The Rust API currently only exposes `component_to_configuration`.
+> For other fields, use the generic `call()` method.
 
 ## Sample Greengrass Components
 

cpp/include/gg/ipc/client.hpp

@@ -22,6 +22,7 @@
 #include <utility>
 
 extern "C" {
+#include <gg/ipc/client.h>
 #include <gg/ipc/types.h>
 }
 
@@ -162,6 +163,23 @@ class Client {
     /// <https://docs.aws.amazon.com/greengrass/v2/developerguide/ipc-local-deployments-components.html#ipc-operation-restartcomponent>
     std::error_code restart_component(std::string_view component_name) noexcept;
 
+    /// Create a local deployment on the core device.
+    /// Triggers a local deployment that can merge configuration into
+    /// components, add/remove root components, and specify local
+    /// recipe/artifact paths.
+    ///
+    /// On Classic Nucleus: requires a dependency on `aws.greengrass.Cli` and an
+    /// access-control policy allowing `aws.greengrass#CreateLocalDeployment`.
+    /// On Nucleus Lite: handled natively by ggdeploymentd — no dependency or
+    /// ACL required.
+    /// See:
+    /// <https://docs.aws.amazon.com/greengrass/v2/developerguide/ipc-local-deployments-components.html#ipc-operation-createlocaldeployment>
+    std::error_code create_local_deployment(
+        const GgCreateLocalDeploymentArgs &args,
+        std::span<std::byte> deployment_id_mem = {},
+        std::string_view *deployment_id = nullptr
+    ) noexcept;
+
     /// Get component configuration value.
     /// Retrieves configuration for the specified key path.
     /// Pass empty span for complete config.

cpp/src/ipc/create_local_deployment.cpp

@@ -0,0 +1,35 @@
+// aws-greengrass-component-sdk - Lightweight AWS IoT Greengrass SDK
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+#include <gg/ipc/client.hpp>
+#include <cstddef>
+#include <span>
+#include <string_view>
+#include <system_error>
+
+extern "C" {
+#include <gg/ipc/client.h>
+}
+
+namespace gg::ipc {
+
+std::error_code Client::create_local_deployment(
+    const GgCreateLocalDeploymentArgs &args,
+    std::span<std::byte> deployment_id_mem,
+    std::string_view *deployment_id
+) noexcept {
+    GgBuffer id_mem = { reinterpret_cast<uint8_t *>(deployment_id_mem.data()),
+                        deployment_id_mem.size() };
+    GgBuffer id_out = {};
+    auto err = ggipc_create_local_deployment(
+        &args, id_mem, deployment_id != nullptr ? &id_out : nullptr
+    );
+    if ((deployment_id != nullptr) && (err == GG_ERR_OK)) {
+        *deployment_id
+            = { reinterpret_cast<const char *>(id_out.data), id_out.len };
+    }
+    return err;
+}
+
+}