feat(build): integrate frontend build into backend binary and update scripts

build-win-x86_64.sh

@@ -1,27 +1,30 @@
 #!/usr/bin/env bash
 #
 # Builds the Windows (amd64) binary.
-#   ./build-win-x86_64.sh              backend only
-#   ./build-win-x86_64.sh --frontend   also build the Vue frontend
 #
-# The frontend is needed at runtime: web/ serves it from frontend/dist.
+# The Vue console is built first and embedded into the binary (web/dist, see
+# web/embed.go), so the executable serves the whole frontend on its own —
+# neither frontend/ nor web/dist/ is needed where it runs.
 set -euo pipefail
 
 # Build from the repository root, however the script was invoked.
 cd "$(dirname "$0")"
 
-BUILD_FRONTEND=0
-if [ "${1:-}" = "--frontend" ]; then
-    BUILD_FRONTEND=1
-fi
-
-if [ "$BUILD_FRONTEND" = "1" ]; then
-    echo "Building frontend..."
-    (
-        cd frontend
+echo "Building frontend..."
+(
+    cd frontend
+    # node_modules is gitignored, so a fresh checkout (CI included) installs
+    # from the lockfile; a warm tree only rebuilds.
+    if [ ! -d node_modules ]; then
         npm ci
-        npm run build
-    )
+    fi
+    npm run build
+)
+
+# go:embed on web/dist fails anyway, but this names the real problem.
+if [ ! -f web/dist/index.html ]; then
+    echo "Frontend build produced no web/dist/index.html" >&2
+    exit 1
 fi
 
 echo "Building for Windows (amd64)..."