Fix pressbooks.sh: docker compose up never ran after a successful build

"if ! docker compose build && docker compose up -d" only negates the
build command's exit status, so on a normal successful build the whole
&&-chain short-circuited false and docker compose up -d never executed —
no containers started, no pressbooks_net network created, so every
following wp-cli call ("docker run --network pressbooks_net ...") failed
with "network pressbooks_net not found". Split into two separate checks.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01P1Xynq3mBwtH45f8bTDfta

services/pressbooks.sh

@@ -641,8 +641,12 @@ PBENV
     log_success "Pressbooks configured at $DIR (port $WEB_PORT)"
     log_info "Building image (first build downloads PrinceXML and cover-generator packages — can take a few minutes)..."
 
-    if ! docker compose build && docker compose up -d; then
-        log_error "Failed to build/start — check: docker compose logs"
+    if ! docker compose build; then
+        log_error "Image build failed — check the output above."
+        return 1
+    fi
+    if ! docker compose up -d; then
+        log_error "Failed to start — check: docker compose logs"
         return 1
     fi