refactor: phase 6 cleanup — RAII handles and io::restore split

- AccountProfileHandle RAII wrapper in handles.hpp; applied in
  account.cpp (getUser, iconPath) replacing manual accountProfileClose
- FILE* in iconPath replaced with existing FileHandle RAII wrapper
- io::restore split into clearSaveRoot + extractAndCommit static helpers;
  public signature unchanged
- sendAll/recvAll kept as bool — callers don't propagate the error string,
  Result<void> would add noise without benefit

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/domain/account.cpp

@@ -28,6 +28,7 @@
 #include <sys/stat.h>
 
 #include <nxst/domain/account.hpp>
+#include <nxst/infra/fs/handles.hpp>
 
 static std::map<AccountUid, User> mUsers;
 
@@ -59,15 +60,15 @@ std::vector<AccountUid> Account::ids(void) {
 
 static User getUser(AccountUid id) {
     User user{id, ""};
-    AccountProfile profile;
+    nxst::AccountProfileHandle profile;
     AccountProfileBase profilebase;
     memset(&profilebase, 0, sizeof(profilebase));
 
-    if (R_SUCCEEDED(accountGetProfile(&profile, id))) {
-        if (R_SUCCEEDED(accountProfileGet(&profile, NULL, &profilebase))) {
+    if (R_SUCCEEDED(accountGetProfile(profile.get(), id))) {
+        profile.valid = true;
+        if (R_SUCCEEDED(accountProfileGet(profile.get(), NULL, &profilebase))) {
             user.name = std::string(profilebase.nickname);
         }
-        accountProfileClose(&profile);
     }
     return user;
 }
@@ -95,28 +96,24 @@ std::string Account::iconPath(AccountUid id) {
     mkdir("sdmc:/switch/NXST", 0755);
     mkdir("sdmc:/switch/NXST/cache", 0755);
 
-    AccountProfile profile;
-    if (R_FAILED(accountGetProfile(&profile, id)))
+    nxst::AccountProfileHandle profile;
+    if (R_FAILED(accountGetProfile(profile.get(), id)))
         return "";
+    profile.valid = true;
 
     u32 imgSize = 0;
-    if (R_FAILED(accountProfileGetImageSize(&profile, &imgSize)) || imgSize == 0) {
-        accountProfileClose(&profile);
+    if (R_FAILED(accountProfileGetImageSize(profile.get(), &imgSize)) || imgSize == 0)
         return "";
-    }
 
     std::vector<u8> buf(imgSize);
     u32 outSize = 0;
-    Result r = accountProfileLoadImage(&profile, buf.data(), imgSize, &outSize);
-    accountProfileClose(&profile);
-    if (R_FAILED(r) || outSize == 0)
+    if (R_FAILED(accountProfileLoadImage(profile.get(), buf.data(), imgSize, &outSize)) || outSize == 0)
         return "";
 
-    FILE* f = fopen(path, "wb");
+    nxst::FileHandle f(fopen(path, "wb"));
     if (!f)
         return "";
-    fwrite(buf.data(), 1, outSize, f);
-    fclose(f);
+    fwrite(buf.data(), 1, outSize, f.get());
     return std::string(path);
 }