ci: push script file to workspace instead of bash -c for #71 (Phase 4)

coder ssh mangles newlines in multi-line bash -c arguments regardless of
quoting style. Push the script via heredoc+cat into a temp file, then
run the file in a separate coder ssh call — no quoting issues and no
stdin sharing with ddev start.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: rfay

.github/workflows/integration-test.yml

@@ -147,19 +147,20 @@ jobs:
 
       - name: Verify workspace — DDEV can start a project
         run: |
-          coder ssh ${{ env.WORKSPACE_NAME }} -- env CI=${{ env.CI }} DDEV_NONINTERACTIVE=${{ env.DDEV_NONINTERACTIVE }} NO_COLOR=${{ env.NO_COLOR }} bash -c '
-            set -euo pipefail
-            TESTDIR=/tmp/ci-ddev-${{ github.run_id }}
-            echo "--- Creating test project in $TESTDIR ---"
-            mkdir -p "$TESTDIR" && cd "$TESTDIR"
-            ddev config --project-type=php --docroot=web
-            echo "--- Starting DDEV project ---"
-            ddev start -y
-            echo "--- Deleting DDEV project ---"
-            ddev delete --omit-snapshot -y
-            rm -rf "$TESTDIR"
-            echo "--- DDEV test complete ---"
-          '
+          coder ssh ${{ env.WORKSPACE_NAME }} -- bash -c 'cat > /tmp/ddev-ci-test.sh' << 'SCRIPT'
+          set -euo pipefail
+          TESTDIR=/tmp/ci-ddev-${{ github.run_id }}
+          echo "--- Creating test project in $TESTDIR ---"
+          mkdir -p "$TESTDIR" && cd "$TESTDIR"
+          ddev config --project-type=php --docroot=web
+          echo "--- Starting DDEV project ---"
+          ddev start -y
+          echo "--- Deleting DDEV project ---"
+          ddev delete --omit-snapshot -y
+          rm -rf "$TESTDIR"
+          echo "--- DDEV test complete ---"
+          SCRIPT
+          coder ssh ${{ env.WORKSPACE_NAME }} -- env CI=${{ env.CI }} DDEV_NONINTERACTIVE=${{ env.DDEV_NONINTERACTIVE }} NO_COLOR=${{ env.NO_COLOR }} bash /tmp/ddev-ci-test.sh
 
       - name: Delete workspace
         if: always()