Adds support for additional/unknown properties on project/service config

cli/azd/.github/copilot-instructions.md

@@ -96,6 +96,19 @@ All Go files must include Microsoft copyright header:
 // Licensed under the MIT License.
 ```
 
+## Extensions Development
+
+### Building Extensions
+Extensions are located in `extensions/` directory and use the extension framework:
+```bash
+# Build and install extension (example using demo extension)
+cd extensions/microsoft.azd.demo
+azd x build
+
+# Test extension (using extension's namespace from extension.yaml)
+azd demo <command>
+```
+
 ## MCP Tools Development
 
 ### Tool Pattern

cli/azd/docs/extension-framework.md

@@ -1114,7 +1114,7 @@ The following are a list of available gRPC services for extension developer to i
 
 ### Project Service
 
-This service manages project configuration retrieval and related operations.
+This service manages project configuration retrieval and related operations, including project and service-level configuration management.
 
 > See [project.proto](../grpc/proto/project.proto) for more details.
 
@@ -1141,6 +1141,107 @@ Adds a new service to the project.
     - `service`: _ServiceConfig_
 - **Response:** _EmptyResponse_
 
+#### GetConfigSection
+
+Retrieves a project configuration section by path from AdditionalProperties.
+
+- **Request:** _GetProjectConfigSectionRequest_
+  - `path` (string): Dot-notation path to the config section
+- **Response:** _GetProjectConfigSectionResponse_
+  - Contains:
+    - `section` (google.protobuf.Struct): The configuration section
+    - `found` (bool): Whether the section exists
+
+#### SetConfigSection
+
+Sets a project configuration section at the specified path in AdditionalProperties.
+
+- **Request:** _SetProjectConfigSectionRequest_
+  - `path` (string): Dot-notation path to the config section
+  - `section` (google.protobuf.Struct): The configuration section to set
+- **Response:** _EmptyResponse_
+
+#### GetConfigValue
+
+Retrieves a single project configuration value by path from AdditionalProperties.
+
+- **Request:** _GetProjectConfigValueRequest_
+  - `path` (string): Dot-notation path to the config value
+- **Response:** _GetProjectConfigValueResponse_
+  - Contains:
+    - `value` (google.protobuf.Value): The configuration value
+    - `found` (bool): Whether the value exists
+
+#### SetConfigValue
+
+Sets a single project configuration value at the specified path in AdditionalProperties.
+
+- **Request:** _SetProjectConfigValueRequest_
+  - `path` (string): Dot-notation path to the config value
+  - `value` (google.protobuf.Value): The configuration value to set
+- **Response:** _EmptyResponse_
+
+#### UnsetConfig
+
+Removes a project configuration value or section at the specified path from AdditionalProperties.
+
+- **Request:** _UnsetProjectConfigRequest_
+  - `path` (string): Dot-notation path to the config to remove
+- **Response:** _EmptyResponse_
+
+#### GetServiceConfigSection
+
+Retrieves a service configuration section by path from service AdditionalProperties.
+
+- **Request:** _GetServiceConfigSectionRequest_
+  - `service_name` (string): Name of the service
+  - `path` (string): Dot-notation path to the config section
+- **Response:** _GetServiceConfigSectionResponse_
+  - Contains:
+    - `section` (google.protobuf.Struct): The configuration section
+    - `found` (bool): Whether the section exists
+
+#### SetServiceConfigSection
+
+Sets a service configuration section at the specified path in service AdditionalProperties.
+
+- **Request:** _SetServiceConfigSectionRequest_
+  - `service_name` (string): Name of the service
+  - `path` (string): Dot-notation path to the config section
+  - `section` (google.protobuf.Struct): The configuration section to set
+- **Response:** _EmptyResponse_
+
+#### GetServiceConfigValue
+
+Retrieves a single service configuration value by path from service AdditionalProperties.
+
+- **Request:** _GetServiceConfigValueRequest_
+  - `service_name` (string): Name of the service
+  - `path` (string): Dot-notation path to the config value
+- **Response:** _GetServiceConfigValueResponse_
+  - Contains:
+    - `value` (google.protobuf.Value): The configuration value
+    - `found` (bool): Whether the value exists
+
+#### SetServiceConfigValue
+
+Sets a single service configuration value at the specified path in service AdditionalProperties.
+
+- **Request:** _SetServiceConfigValueRequest_
+  - `service_name` (string): Name of the service
+  - `path` (string): Dot-notation path to the config value
+  - `value` (google.protobuf.Value): The configuration value to set
+- **Response:** _EmptyResponse_
+
+#### UnsetServiceConfig
+
+Removes a service configuration value or section at the specified path from service AdditionalProperties.
+
+- **Request:** _UnsetServiceConfigRequest_
+  - `service_name` (string): Name of the service
+  - `path` (string): Dot-notation path to the config to remove
+- **Response:** _EmptyResponse_
+
 ---
 
 ### Environment Service