fix: address review — use pip install uv, fix import command, update docs

- Replace COPY --from with pip install uv==0.11.14 to fully eliminate
  third-party image pull at build time
- Update agentcore import Dockerfile generation to use AWS ECR base image
- Update docs/container-builds.md to reflect new base image setup

Constraint: No AWS-hosted uv binary available; pip install is the cleanest path
Confidence: high
Scope-risk: narrow

Author: jesseturner21

docs/container-builds.md

@@ -39,7 +39,8 @@ app/MyAgent/
 
 ## Generated Dockerfile
 
-The template uses `ghcr.io/astral-sh/uv:python3.12-bookworm-slim` as the base image with these design choices:
+The template uses `public.ecr.aws/docker/library/python:3.12-slim` as the base image (with `uv` installed via
+`pip install uv==0.11.14`) with these design choices:
 
 - **Layer caching**: Dependencies (`pyproject.toml`) are installed before copying application code
 - **Non-root**: Runs as `bedrock_agentcore` (UID 1000)

src/assets/__tests__/__snapshots__/dockerfile-render.test.ts.snap

@@ -3,7 +3,7 @@
 exports[`Dockerfile enableOtel rendering > renders opentelemetry-instrument CMD when enableOtel is true > Dockerfile-enableOtel-true 1`] = `
 "FROM public.ecr.aws/docker/library/python:3.12-slim
 
-COPY --from=ghcr.io/astral-sh/uv:latest /uv /uvx /usr/local/bin/
+RUN pip install --no-cache-dir uv==0.11.14
 
 ARG UV_DEFAULT_INDEX
 ARG UV_INDEX
@@ -43,7 +43,7 @@ CMD ["opentelemetry-instrument", "python", "-m", "main"]
 exports[`Dockerfile enableOtel rendering > renders plain python CMD when enableOtel is false > Dockerfile-enableOtel-false 1`] = `
 "FROM public.ecr.aws/docker/library/python:3.12-slim
 
-COPY --from=ghcr.io/astral-sh/uv:latest /uv /uvx /usr/local/bin/
+RUN pip install --no-cache-dir uv==0.11.14
 
 ARG UV_DEFAULT_INDEX
 ARG UV_INDEX

src/assets/container/python/Dockerfile

@@ -1,6 +1,6 @@
 FROM public.ecr.aws/docker/library/python:3.12-slim
 
-COPY --from=ghcr.io/astral-sh/uv:latest /uv /uvx /usr/local/bin/
+RUN pip install --no-cache-dir uv==0.11.14
 
 ARG UV_DEFAULT_INDEX
 ARG UV_INDEX

src/cli/commands/import/actions.ts

@@ -383,7 +383,8 @@ export async function handleImport(options: ImportOptions): Promise<ImportResult
               fs.writeFileSync(
                 destDockerfile,
                 [
-                  'FROM ghcr.io/astral-sh/uv:python3.12-bookworm-slim',
+                  'FROM public.ecr.aws/docker/library/python:3.12-slim',
+                  'RUN pip install --no-cache-dir uv==0.11.14',
                   'WORKDIR /app',
                   '',
                   'ENV UV_SYSTEM_PYTHON=1 \\',