fix: Docker must redeclare args in multi-stage builds; fix path in docs (#916)

* Redeclare `ARG` after `FROM` stage to ensure visibility.
* Fix path typo in documentation (should reference NeMo Agent toolkit rather than example)

Closes nvbugs-5561420

## By Submitting this PR I confirm:
- I am familiar with the [Contributing Guidelines](https://github.com/NVIDIA/NeMo-Agent-Toolkit/blob/develop/docs/source/resources/contributing.md).
- We require that all contributors "sign-off" on their commits. This certifies that the contribution is your original work, or you have rights to submit it under the same license, or a compatible license.
  - Any contribution which contains commits that are not Signed-Off will not be accepted.
- When the PR is ready for review, new or existing tests cover these changes.
- When the PR is ready for review, the documentation is up to date with these changes.




## Summary by CodeRabbit

- New Features
  - Docker images now support configurable build-time versions for Python, UV, and NAT via build arguments.
  - UV binaries are bundled during build for faster, reproducible environments.
  - Build-time validation ensures NAT version is provided.

- Chores
  - Standardized build-arg declarations across example Dockerfiles for consistency and easier parameterization.

- Documentation
  - Updated example guides to reference the NeMo Agent toolkit repository.
  - Refreshed Docker build instructions to align with the new configurable build args.

Authors:
  - Will Killian (https://github.com/willkill07)

Approvers:
  - Eric Evans II (https://github.com/ericevans-nv)

URL: #916

Author: willkill07

docker/Dockerfile

@@ -22,6 +22,10 @@ ARG NAT_VERSION
 
 FROM --platform=$TARGETPLATFORM ${BASE_IMAGE_URL}:${BASE_IMAGE_TAG}
 
+ARG PYTHON_VERSION
+ARG UV_VERSION
+ARG NAT_VERSION
+
 COPY --from=ghcr.io/astral-sh/uv:${UV_VERSION} /uv /uvx /bin/
 
 ENV PYTHONDONTWRITEBYTECODE=1

examples/evaluation_and_profiling/email_phishing_analyzer/Dockerfile

@@ -22,6 +22,10 @@ ARG NAT_VERSION
 
 FROM ${BASE_IMAGE_URL}:${BASE_IMAGE_TAG}
 
+ARG PYTHON_VERSION
+ARG UV_VERSION
+ARG NAT_VERSION
+
 COPY --from=ghcr.io/astral-sh/uv:${UV_VERSION} /uv /uvx /bin/
 
 ENV PYTHONDONTWRITEBYTECODE=1

examples/evaluation_and_profiling/email_phishing_analyzer/README.md

@@ -225,7 +225,7 @@ For a production deployment, use Docker:
 
 Prior to building the Docker image ensure that you have followed the steps in the [Installation and Setup](#installation-and-setup) section, and you are currently in the NeMo Agent toolkit virtual environment.
 
-From the root directory of the Simple Calculator repository, build the Docker image:
+From the root directory of the NeMo Agent toolkit repository, build the Docker image:
 
 ```bash
 docker build --build-arg NAT_VERSION=$(python -m setuptools_scm) -t email_phishing_analyzer -f examples/evaluation_and_profiling/email_phishing_analyzer/Dockerfile .

examples/frameworks/agno_personal_finance/Dockerfile

@@ -22,6 +22,10 @@ ARG NAT_VERSION
 
 FROM ${BASE_IMAGE_URL}:${BASE_IMAGE_TAG}
 
+ARG PYTHON_VERSION
+ARG UV_VERSION
+ARG NAT_VERSION
+
 COPY --from=ghcr.io/astral-sh/uv:${UV_VERSION} /uv /uvx /bin/
 
 ENV PYTHONDONTWRITEBYTECODE=1

examples/getting_started/simple_calculator/Dockerfile

@@ -22,6 +22,10 @@ ARG NAT_VERSION
 
 FROM ${BASE_IMAGE_URL}:${BASE_IMAGE_TAG}
 
+ARG PYTHON_VERSION
+ARG UV_VERSION
+ARG NAT_VERSION
+
 COPY --from=ghcr.io/astral-sh/uv:${UV_VERSION} /uv /uvx /bin/
 
 ENV PYTHONDONTWRITEBYTECODE=1

examples/getting_started/simple_calculator/README.md

@@ -87,7 +87,7 @@ For a production deployment, use Docker:
 
 Prior to building the Docker image ensure that you have followed the steps in the [Installation and Setup](#installation-and-setup) section, and you are currently in the NeMo Agent toolkit virtual environment.
 
-From the root directory of the Simple Calculator repository, build the Docker image:
+From the root directory of the NeMo Agent toolkit repository, build the Docker image:
 
 ```bash
 docker build --build-arg NAT_VERSION=$(python -m setuptools_scm) -t simple_calculator -f examples/getting_started/simple_calculator/Dockerfile .

examples/getting_started/simple_web_query/Dockerfile

@@ -22,6 +22,10 @@ ARG NAT_VERSION
 
 FROM ${BASE_IMAGE_URL}:${BASE_IMAGE_TAG}
 
+ARG PYTHON_VERSION
+ARG UV_VERSION
+ARG NAT_VERSION
+
 COPY --from=ghcr.io/astral-sh/uv:${UV_VERSION} /uv /uvx /bin/
 
 ENV PYTHONDONTWRITEBYTECODE=1