fix: Default CI_USE_BUILD_INSTANCE_KEY to 1 in bootstrap_ec2

Per Adam's feedback, default the env var at the top of bootstrap_ec2
rather than in ci3.yml. This is consistent with how CI=1 is set there.

External CI (ci3-external.yml) explicitly sets it to "0" to disable
build instance key features for external contributors.

Author: johnathan79717

.github/workflows/ci3.yml

@@ -85,8 +85,6 @@ jobs:
           PR_COMMITS: ${{ github.event.pull_request.commits }}
           PR_NUMBER: ${{ github.event.pull_request.number }}
           GITHUB_REF_NAME: ${{ github.ref_name }}
-          # Enable build instance key features (disk logging, benchmark uploads, etc.)
-          CI_USE_BUILD_INSTANCE_KEY: "1"
         # NOTE: $CI_MODE is set in the Determine CI Mode step.
         run: ./.github/ci3.sh $CI_MODE
 

ci3/bootstrap_ec2

@@ -8,6 +8,9 @@ NO_TERMINATE=${NO_TERMINATE:-0}
 
 # We're always "in CI" if we're running on a remote instance.
 export CI=1
+# Enable build instance key features (disk logging, benchmark uploads) by default.
+# Set to 0 in ci3-external.yml for external contributors who don't have SSH access.
+export CI_USE_BUILD_INSTANCE_KEY=${CI_USE_BUILD_INSTANCE_KEY:-1}
 
 if [ "$arch" == "arm64" ]; then
   cores=64