Adapt ec2-gha to Lambda Labs API

- Rename `ec2_gha` → `lambda_gha` throughout
- Replace boto3 with requests for Lambda Labs REST API
- Simplify action.yml inputs (no VPC, IAM, CloudWatch, security groups)
- Rewrite runner.yml workflow (API key auth instead of AWS OIDC)
- Update termination to call Lambda API instead of `shutdown -h now`
- Remove AWS-specific demo workflows, keep minimal GPU demo
- Simplify README for Lambda Labs

Known TODOs:
- SSH-based setup (Lambda doesn't support cloud-init userdata)
- Update tests to mock requests instead of boto3/moto

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: ryan-williams

.github/workflows/README.md

@@ -49,7 +49,7 @@ jobs:
       - name: Run tests
         run: |
           cd tests/
-          pytest -v --cov=ec2_gha --cov-report=xml --color=yes .
+          pytest -v --cov=lambda_gha --cov-report=xml --color=yes .
 
       - name: CodeCov
         uses: codecov/codecov-action@v4

.github/workflows/ci.yaml

@@ -1,20 +1,19 @@
-name: Demo – minimal EC2 GPU job
+name: Demo – minimal Lambda GPU job
 on:
   workflow_dispatch:
-  workflow_call:   # Tested by `demos.yml`
+  workflow_call:
 permissions:
-  id-token: write  # Required for AWS OIDC authentication
-  contents: read   # Required for actions/checkout; normally set by default, but must explicitly specify when defining a custom `permissions` block.
+  contents: read
 jobs:
-  ec2:
-    # To use from another repo: Open-Athena/ec2-gha/.github/workflows/runner.yml@v2
+  lambda:
+    # To use from another repo: Open-Athena/lambda-gha/.github/workflows/runner.yml@main
     uses: ./.github/workflows/runner.yml
     secrets: inherit
     with:
-      ec2_instance_type: g4dn.xlarge       # ≈$0.56/hr GPU instance: https://instances.vantage.sh/aws/ec2/g4dn.xlarge
-      ec2_image_id: ami-00096836009b16a22  # Deep Learning OSS Nvidia Driver AMI GPU PyTorch 2.4.1 (Ubuntu 22.04) 20250302
+      instance_type: gpu_1x_a10  # Single A10 GPU
+      region: us-south-1
   gpu-test:
-    needs: ec2
-    runs-on: ${{ needs.ec2.outputs.id }}
+    needs: lambda
+    runs-on: ${{ needs.lambda.outputs.id }}
     steps:
     - run: nvidia-smi  # Verify GPU is available