feat(eliminate-frontend-makefile): task 3.2 - fix deploy-ha.sh/run.sh messages

Rewords deploy-ha.sh's block comment and two fallback echo lines, and
run.sh's XCE-not-found error, to stop naming the now-deleted
Makefile's build-server/build-cli targets, pointing at /xce-build
apiserver instead. Discovery/control-flow logic in both files is
unchanged (verified line-by-line: no if/elif/else lines touched);
run.sh's XCE default placeholder is untouched by design.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XYdtrEWWZfKRRGED7raEYg

src/frontend/tests/regression/run.sh

@@ -66,7 +66,7 @@ echo ""
 
 if [[ ! -x "$XCE" ]]; then
     echo "ERROR: xce binary not found at $XCE"
-    echo "Build with: cd xcecli && CGO_ENABLED=0 go build -o /tmp/xce_static ./cmd/main.go"
+    echo "Build with: /xce-build apiserver"
     exit 1
 fi