Optimize workflow setup and cleanup for lower resource use

.forgejo/workflows/deploy-cfn.yml

@@ -14,6 +14,7 @@ jobs:
       AWS_SESSION_TOKEN: ${{ secrets.AWS_SESSION_TOKEN }}
       AWS_DEFAULT_REGION: us-east-1
       LOWER: ${{ secrets.LOWER }}
+      PIP_NO_CACHE_DIR: "1"
 
     steps:
       - name: Prepare source
@@ -32,6 +33,14 @@ jobs:
       - name: Ensure AWS CLI
         run: |
           set -e
+
+          # Fast path: aws may already be installed in user bin from a prior run.
+          if [ -x "$HOME/.local/bin/aws" ]; then
+            echo "$HOME/.local/bin" >> "$GITHUB_PATH"
+            "$HOME/.local/bin/aws" --version
+            exit 0
+          fi
+
           if command -v aws >/dev/null 2>&1; then
             aws --version
             exit 0
@@ -40,6 +49,7 @@ jobs:
           # Try local AWS CLI v2 install (no root required).
           if command -v curl >/dev/null 2>&1 && command -v unzip >/dev/null 2>&1; then
             TMP_DIR="$(mktemp -d)"
+            trap 'rm -rf "${TMP_DIR}"' EXIT
             curl -fsSL "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" -o "${TMP_DIR}/awscliv2.zip"
             unzip -q "${TMP_DIR}/awscliv2.zip" -d "${TMP_DIR}"
             "${TMP_DIR}/aws/install" -i "$HOME/.aws-cli" -b "$HOME/.local/bin" || true
@@ -52,7 +62,7 @@ jobs:
 
           # Fallback to pip user install.
           if command -v python3 >/dev/null 2>&1; then
-            python3 -m pip install --user --upgrade awscli
+            python3 -m pip install --user --upgrade --no-cache-dir awscli
             echo "$HOME/.local/bin" >> "$GITHUB_PATH"
             "$HOME/.local/bin/aws" --version
             exit 0
@@ -128,3 +138,9 @@ jobs:
             --stack-name hello-lambda-stack \
             --template-file "${SRC_DIR}/infra/hello-lambda.yml" \
             --capabilities CAPABILITY_NAMED_IAM
+
+      - name: Cleanup workspace artifacts
+        if: always()
+        run: |
+          rm -rf _src
+          rm -rf "$HOME/.cache/pip" || true