fix: change library name variables to constants

Co-authored-by: Copilot <copilot@github.com>

Author: dongwlin

internal/native/agent_client.go

@@ -8,10 +8,9 @@ import (
 	"github.com/ebitengine/purego"
 )
 
-var (
-	maaAgentClient     uintptr
-	maaAgentClientName = "MaaAgentClient"
-)
+var maaAgentClient uintptr
+
+const maaAgentClientName = "MaaAgentClient"
 
 var (
 	MaaAgentClientCreateV2                 func(identifier uintptr) uintptr

internal/native/agent_server.go

@@ -9,10 +9,9 @@ import (
 	"github.com/ebitengine/purego"
 )
 
-var (
-	maaAgentServer     uintptr
-	maaAgentServerName = "MaaAgentServer"
-)
+var maaAgentServer uintptr
+
+const maaAgentServerName = "MaaAgentServer"
 
 var (
 	MaaAgentServerRegisterCustomRecognition func(name string, recognition MaaCustomRecognitionCallback, transArg unsafe.Pointer) bool

internal/native/framework.go

@@ -9,10 +9,9 @@ import (
 	"github.com/ebitengine/purego"
 )
 
-var (
-	maaFramework     uintptr
-	maaFrameworkName = "MaaFramework"
-)
+var maaFramework uintptr
+
+const maaFrameworkName = "MaaFramework"
 
 var (
 	MaaVersion func() string

internal/native/toolkit.go

@@ -9,10 +9,9 @@ import (
 	"github.com/ebitengine/purego"
 )
 
-var (
-	maaToolkit     uintptr
-	maaToolkitName = "MaaToolkit"
-)
+var maaToolkit uintptr
+
+const maaToolkitName = "MaaToolkit"
 
 var MaaToolkitConfigInitOption func(userPath, defaultJson string) bool