permission: reuse cached env strings

Permission::is_scope_granted() and Permission::Drop() built the
"permission" and "resource" diagnostics message keys with
FIXED_ONE_BYTE_STRING(isolate, ...) on every publish, even though
Environment already caches these exact strings via
env->permission_string() and env->resource_string()
(src/env_properties.h). One call site in the same file already used
the cached accessor; these two did not, and Environment is already
in scope at both sites.

Assisted-by: Claude Sonnet 5
Signed-off-by: agape1225 <49804691+agape1225@users.noreply.github.com>

Author: agape1225

src/permission/permission.cc

@@ -257,11 +257,11 @@ bool Permission::is_scope_granted(Environment* env,
             v8::Object::New(isolate, v8::Null(isolate), nullptr, nullptr, 0);
         const char* perm_str = PermissionToString(permission);
         msg->Set(context,
-                 FIXED_ONE_BYTE_STRING(isolate, "permission"),
+                 env->permission_string(),
                  v8::String::NewFromUtf8(isolate, perm_str).ToLocalChecked())
             .Check();
         msg->Set(context,
-                 FIXED_ONE_BYTE_STRING(isolate, "resource"),
+                 env->resource_string(),
                  v8::String::NewFromUtf8(isolate,
                                          res.data(),
                                          v8::NewStringType::kNormal,
@@ -327,11 +327,11 @@ void Permission::Drop(Environment* env,
           v8::Object::New(isolate, v8::Null(isolate), nullptr, nullptr, 0);
       const char* perm_str = PermissionToString(scope);
       msg->Set(context,
-               FIXED_ONE_BYTE_STRING(isolate, "permission"),
+               env->permission_string(),
                v8::String::NewFromUtf8(isolate, perm_str).ToLocalChecked())
           .Check();
       msg->Set(context,
-               FIXED_ONE_BYTE_STRING(isolate, "resource"),
+               env->resource_string(),
                v8::String::NewFromUtf8(isolate,
                                        param.data(),
                                        v8::NewStringType::kNormal,