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

run.bat

@@ -1,12 +1,20 @@
-@echo off
-setlocal enabledelayedexpansion
-
-:: Get git commit hash (shortened to 7 characters, can also use full)
-for /f %%i in ('git rev-parse --short HEAD') do set COMMIT=%%i
-
-:: Get UTC time
-for /f %%i in ('powershell -Command "Get-Date -Format 'yyyy-MM-ddTHH:mm:ssZ'"') do set BUILD_DATE=%%i
-
-:: Build -ldflags
-set LDFLAGS=-X main.BuildTime=%BUILD_DATE% -X main.CommitHash=%COMMIT%
+@echo off
+setlocal enabledelayedexpansion
+
+:: The console is embedded in the binary (web\embed.go), so compiling without
+:: web\dist fails. Say that plainly rather than leaving go:embed's error.
+if not exist "web\dist\index.html" (
+    echo The web console is not built: web\dist is missing.
+    echo Run build-win-x86_64.bat once, or "npm run build" in frontend\.
+    exit /b 1
+)
+
+:: Get git commit hash (shortened to 7 characters, can also use full)
+for /f %%i in ('git rev-parse --short HEAD') do set COMMIT=%%i
+
+:: Get UTC time
+for /f %%i in ('powershell -Command "Get-Date -Format 'yyyy-MM-ddTHH:mm:ssZ'"') do set BUILD_DATE=%%i
+
+:: Build -ldflags
+set LDFLAGS=-X main.BuildTime=%BUILD_DATE% -X main.CommitHash=%COMMIT%
 go run -ldflags "%LDFLAGS%" .