refactor: move Wasm related code to pkg/common/wasm

pkg/common/wasm/wasm.go

@@ -0,0 +1,34 @@
+//go:build js && wasm
+// +build js,wasm
+
+package wasm
+
+import (
+	"encoding/base64"
+	"encoding/json"
+
+	"github.com/labstack/echo/v4"
+)
+
+func ContextMiddleware(next echo.HandlerFunc) echo.HandlerFunc {
+	return func(c echo.Context) error {
+		// Extract WASM context from headers
+		if wasmCtx := c.Request().Header.Get("X-Wasm-Context"); wasmCtx != "" {
+			if ctx, err := DecodeWasmContext(wasmCtx); err == nil {
+				c.Set("wasm_context", ctx)
+			}
+		}
+		return next(c)
+	}
+}
+
+// decodeWasmContext decodes the WASM context from a base64 encoded string
+func DecodeWasmContext(ctx string) (map[string]any, error) {
+	decoded, err := base64.StdEncoding.DecodeString(ctx)
+	if err != nil {
+		return nil, err
+	}
+	var ctxData map[string]any
+	err = json.Unmarshal(decoded, &ctxData)
+	return ctxData, err
+}