fix: various bug fixes in desktop components

programs/src/desktop/apps/filemanager/filesystem.cpp

@@ -243,7 +243,7 @@ void filemanager_read_dir(FileManagerState* fm) {
 
     // Sort: directories first, then alphabetical (case-insensitive)
     for (int i = 1; i < fm->entry_count; i++) {
-        char tmp_name[64];
+        char tmp_name[128];
         int tmp_type = fm->entry_types[i];
         int tmp_size = fm->entry_sizes[i];
         bool tmp_isdir = fm->is_dir[i];
@@ -385,9 +385,11 @@ bool filemanager_delete_recursive(const char* path) {
 }
 
 bool filemanager_copy_file(const char* src, const char* dst) {
+    if (!src || !dst || montauk::streq(src, dst)) return false;
+
     int sfd = montauk::open(src);
     if (sfd < 0) return false;
-    int size = (int)montauk::getsize(sfd);
+    uint64_t size = montauk::getsize(sfd);
 
     // Create destination
     int dfd = montauk::fcreate(dst);
@@ -396,33 +398,46 @@ bool filemanager_copy_file(const char* src, const char* dst) {
         return false;
     }
 
+    bool ok = true;
     if (size > 0) {
-        // Cap at 4 MB to avoid exhausting memory
-        if (size > 4 * 1024 * 1024) {
-            montauk::close(sfd);
-            montauk::close(dfd);
-            montauk::fdelete(dst);
-            return false;
-        }
-        uint8_t* buf = (uint8_t*)montauk::malloc(size);
+        static constexpr uint64_t COPY_CHUNK = 64 * 1024;
+        uint64_t buf_size = size < COPY_CHUNK ? size : COPY_CHUNK;
+        uint8_t* buf = (uint8_t*)montauk::malloc(buf_size);
         if (!buf) {
             montauk::close(sfd);
             montauk::close(dfd);
             montauk::fdelete(dst);
             return false;
         }
-        montauk::read(sfd, buf, 0, size);
-        montauk::fwrite(dfd, buf, 0, size);
+
+        uint64_t off = 0;
+        while (off < size) {
+            uint64_t todo64 = size - off;
+            if (todo64 > buf_size) todo64 = buf_size;
+            int todo = (int)todo64;
+            int got = montauk::read(sfd, buf, off, todo64);
+            if (got != todo) { ok = false; break; }
+            int wrote = montauk::fwrite(dfd, buf, off, todo64);
+            if (wrote != todo) { ok = false; break; }
+            off += todo64;
+        }
+
         montauk::mfree(buf);
     }
 
     montauk::close(sfd);
     montauk::close(dfd);
+    if (!ok) {
+        montauk::fdelete(dst);
+        return false;
+    }
     return true;
 }
 
 // Recursive directory copy
 bool filemanager_copy_dir_recursive(const char* src, const char* dst) {
+    if (!src || !dst || montauk::streq(src, dst)) return false;
+
     montauk::fmkdir(dst);
 
     const char* names[64];