chore: import upstream snapshot with attribution

docs/devguide/running/source.md

@@ -0,0 +1,83 @@
+---
+description: "Building from Source — build and run the Conductor server and UI locally from source for development and testing."
+---
+# Building from source
+
+Build and run Conductor server and UI locally from source. The default configuration uses in-memory persistence with no indexing — all data is lost when the server stops. This setup is for development and testing only.
+
+For persistent backends, use [Docker Compose](deploy.md) or configure a database backend.
+
+
+## Prerequisites
+
+- Java (JDK) 21+
+- (Optional) [Docker](https://www.docker.com/get-started/) for running tests
+
+
+## Building and running the server
+
+1. Clone the repository:
+
+    ```shell
+    git clone https://github.com/conductor-oss/conductor.git
+    cd conductor
+    ```
+
+2. Run with Gradle:
+
+    ```shell
+    cd server
+    ../gradlew bootRun
+    ```
+
+    To use a custom configuration file:
+
+    ```shell
+    CONFIG_PROP=config.properties ../gradlew bootRun
+    ```
+
+3. The server is now running:
+
+    | URL | Description |
+    |:----|:---|
+    | `http://localhost:8080` | Conductor UI |
+    | `http://localhost:8080/swagger-ui/index.html` | REST API docs |
+    | `http://localhost:8080/api/` | API base URL |
+
+
+## Running from a pre-compiled JAR
+
+As an alternative to building from source, download and run the pre-compiled JAR:
+
+```shell
+export CONDUCTOR_VER=3.21.10
+export REPO_URL=https://repo1.maven.org/maven2/org/conductoross/conductor-server
+curl $REPO_URL/$CONDUCTOR_VER/conductor-core-$CONDUCTOR_VER-boot.jar \
+  --output conductor-core-$CONDUCTOR_VER-boot.jar
+java -jar conductor-core-$CONDUCTOR_VER-boot.jar
+```
+
+
+## Running the UI from source
+
+### Prerequisites
+
+- A running Conductor server on port 8080
+- [Node.js](https://nodejs.org) v18+
+- [Yarn](https://classic.yarnpkg.com/en/docs/install)
+
+### Steps
+
+```shell
+cd ui
+yarn install
+yarn run start
+```
+
+The UI is accessible at [http://localhost:5000](http://localhost:5000).
+
+To build compiled assets for production hosting:
+
+```shell
+yarn build
+```