Fix display resolution UI test foreground activation on CI

XCUIApplication.launch() fails to activate the app on headless CI
runners, reporting "Failed to activate application (current state:
Running Background)". With continueAfterFailure=false, this kills the
test before ensureForegroundAfterLaunch can retry.

Fix by temporarily setting continueAfterFailure=true around launch(),
then retrying activation via app.activate(). Also add a retry loop in
the CI workflow since foreground activation is inherently flaky on
headless runners.

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

.github/workflows/ci.yml

@@ -495,12 +495,24 @@ jobs:
           {"helperBinaryPath":"$HELPER_PATH"}
           EOF
 
-          xcodebuild -project GhosttyTabs.xcodeproj -scheme cmux -configuration Debug \
-            -clonedSourcePackagesDirPath "$SOURCE_PACKAGES_DIR" \
-            -disableAutomaticPackageResolution \
-            -destination "platform=macOS" \
-            -only-testing:cmuxUITests/DisplayResolutionRegressionUITests \
-            test
+          # Retry once — foreground activation on headless CI runners is flaky
+          for attempt in 1 2; do
+            if xcodebuild -project GhosttyTabs.xcodeproj -scheme cmux -configuration Debug \
+              -clonedSourcePackagesDirPath "$SOURCE_PACKAGES_DIR" \
+              -disableAutomaticPackageResolution \
+              -destination "platform=macOS" \
+              -only-testing:cmuxUITests/DisplayResolutionRegressionUITests \
+              test; then
+              exit 0
+            fi
+            if [ "$attempt" -eq 2 ]; then
+              echo "Display resolution UI regression failed after 2 attempts" >&2
+              exit 1
+            fi
+            echo "Attempt $attempt failed, retrying..."
+            pkill -x "cmux DEV" 2>/dev/null || true
+            sleep 3
+          done
 
       - name: Run browser find focus UI regression
         run: |