refactor: extract web host runtime and pack it explicitly

Move the host-side web runtime assets into `internal/webruntime/host`
so their ownership is separated from `cmd/ispx` and from platform
templates under `cmd/gox/template/platform`.

Update the web export flow to assemble runtime assets explicitly from
the engine template, embedded host assets, `ispx.wasm`, and
`wasm_exec.js` instead of staging host files through `$GOPATH/bin/ispx`.

Add `packwebruntime` to build release bundles directly and replace the
temporary empty-project export hack in `make_util.sh`.

Also remove XBuilder-specific branding from shared runtime-facing titles
so the base web runtime stays product-neutral.

Signed-off-by: Aofei Sheng <aofei@aofeisheng.com>

Author: aofei

cmd/gox/install.sh

@@ -55,13 +55,6 @@ if [ "$1" = "--web" ]; then
     go env -w GOFLAGS="-buildvcs=false"
     ( cd ../ispx && ./build.sh )
     cp ../ispx/ispx.wasm "$GOPATH/bin/"
-
-    # Install ispx web runtime
-    echo "Installing ispx web runtime..."
-    rm -rf "$GOPATH/bin/ispx"
-    mkdir -p "$GOPATH/bin/ispx"
-    cp ../ispx/web/* "$GOPATH/bin/ispx/"
-    echo "ispx web runtime installed to $GOPATH/bin/ispx/"
 fi
 
 ( cd ../ispxnative && ./build.sh )

cmd/gox/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"embed"
+	"fmt"
 	"strings"
 
 	"github.com/goplus/spx/v2/cmd/gox/pkg/command"
@@ -50,7 +51,7 @@ func main() {
 	// Initialize the Args field if not already initialized
 	err := cmd.RunCmd(appName, appName, cmd.Version, projectFS, "template/project", "project")
 	if err != nil {
-		println("failed to run cmd:", err)
+		fmt.Println("failed to run cmd:", err)
 		return
 	}
 }

cmd/gox/pkg/command/args.go

@@ -72,7 +72,7 @@ func (pself *CmdTool) CheckCmd(ext ...string) bool {
 		"build", "buildtinygo", "rune", "export",
 		"runweb", "buildweb", "exportweb", "stopweb", "runwebworker",
 		"runm", "exportbot", "exportapk", "exportios",
-		"run", "runi", "exporttemplateweb", "exportminigame", "exportminiprogram", "exportwebworker",
+		"run", "runi", "exporttemplateweb", "exportminigame", "exportminiprogram", "exportwebworker", "packwebruntime",
 	}
 	cmds = append(cmds, ext...)
 
@@ -194,6 +194,7 @@ Available commands:
     - exportweb       # Export the web package
     - exportwebworker # Export web worker package
     - exporttemplateweb # Export template web package
+    - packwebruntime  # Pack the reusable web runtime bundle
     - stopweb         # Stop the web server
 
     Export & Distribution:

cmd/gox/pkg/command/cmd.go

@@ -100,6 +100,9 @@ func (cmd *CmdTool) RunCmd(projectName, fileSuffix, version string, fs embed.FS,
 	if cmd.Args.CmdName == "init" {
 		return cmd.Init()
 	}
+	if cmd.Args.CmdName == "packwebruntime" {
+		return cmd.PackWebRuntime()
+	}
 
 	// Setup paths
 	err = cmd.setupPaths(dstRelDir)

cmd/gox/pkg/command/env.go

@@ -247,16 +247,6 @@ func (pself *CmdTool) getWasmPath() string {
 	return filePath
 }
 
-// getIspxWebDir returns the path to the ispx web runtime directory.
-func (pself *CmdTool) getIspxWebDir() (string, error) {
-	ispxWebDir := path.Join(pself.GoBinPath, "ispx")
-	if _, err := os.Stat(ispxWebDir); os.IsNotExist(err) {
-		return "", fmt.Errorf("ispx web runtime not found at %s; "+
-			"run 'cd cmd/gox && ./install.sh --web' to install", ispxWebDir)
-	}
-	return ispxWebDir, nil
-}
-
 // SetupPC sets up the PC environment by running the initialization script
 func (pself *CmdTool) SetupPC() error {
 	// Get current working directory