Package level documenation for common_msgs

Author: gavintranquilino

autonomy/wato_msgs/common_msgs/README.md

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+# Common Messages (common_msgs)
+
+## File Tree/Package Structure
+This message package follows standard ROS2 package scheme:
+```
+common_msgs/
+├── CMakeLists.txt
+├── package.xml
+├── README.md
+└── msg/
+    ├── ArmPose.msg
+    ├── HandPose.msg
+    └── JointState.msg
+```
+
+## Purpose
+The `common_msgs` package serves as a global package for message definitions that are commonly used across various components and packages within the humanoid project. 
+
+## Inputs & Outputs
+This package primarily defines message structures. Therefore:
+-   **Outputs**: Provides `.msg` definitions that other ROS 2 packages can import and use.
+-   **Inputs**: Does not process data or subscribe to topics; it only defines data structures.
+
+## Key Features
+-   **Message Definitions**: Contains a collection of `.msg` files, each defining a specific data structure. These messages are designed to be generic and applicable in multiple contexts.
+
+### Message Definitions
+-   `ArmPose.msg`: Defines the pose of the humanoid arm, including optional HandPose inside.
+-   `HandPose.msg`: Defines the pose of the humanoid hand, including each JointState of each finger's joints.
+-   `JointState.msg`: Defines the state of a joint, including position, velocity, orientation, and effort.
+
+## Usage
+To use the messages defined in this package within another ROS 2 package:
+
+1.  **Copy the package into your Docker image's source workspace**: Add the following line to your Dockerfile (typically `root/docker/MODULE_NAME/MODULE_NAME.Dockerfile`), typically in the section where you copy your source code:
+    ```dockerfile
+    # # Copy in source code
+    # # COPY autonomy/wato_msgs/sample_msgs sample_msgs
+    COPY autonomy/wato_msgs/common_msgs common_msgs
+    ```
+
+2.  **Add Dependency**: Ensure that `common_msgs` is listed as a dependency in the `package.xml` of your consuming package:
+    ```xml
+    <depend>common_msgs</depend>
+    ```
+3.  **Include in CMakeLists.txt** (for C++ packages):
+    ```cmake
+    find_package(common_msgs REQUIRED)
+    ament_target_dependencies(your_target_name common_msgs)
+    ```
+4.  **Import in Python scripts**:
+    ```python
+    from common_msgs.msg import YourMessageName
+    ```
+5.  **Include in C++ code**:
+    ```cpp
+    #include "common_msgs/msg/your_message_name.hpp"
+    ```
+
+### Testing
+Currently, this package primarily contains message definitions, so testing focuses on ensuring they can be correctly compiled and used by dependent packages. 
+
+## Configuration
+-   **Parameters**: No configurable parameters are defined within this package itself.