feat: filesystem and Files app support for >64 file entries, 64-bit sizes, async ops, GUI toolkit improvements to devexplorer app

programs/include/Api/Syscall.hpp

@@ -179,6 +179,9 @@ namespace Montauk {
     // Cross-process graceful power-off request channel
     static constexpr uint64_t SYS_POWER_REQUEST       = 135;
 
+    // Paginated directory read (path, names, max, startIndex)
+    static constexpr uint64_t SYS_READDIR_AT          = 136;
+
     // Graceful power-off request actions (SYS_POWER_REQUEST). The desktop posts
     // a pending action and exits; login.elf reads it, runs the shutdown stages,
     // then issues the matching SYS_SHUTDOWN / SYS_RESET.

programs/include/montauk/syscall.h

@@ -141,6 +141,13 @@ namespace montauk {
     inline int readdir(const char* path, const char** names, int max) {
         return (int)syscall3(Montauk::SYS_READDIR, (uint64_t)path, (uint64_t)names, (uint64_t)max);
     }
+    // Paginated directory read: returns entries [startIndex, startIndex+max).
+    // Call repeatedly with increasing startIndex (advancing by the returned
+    // count) until it returns 0 to enumerate directories of any size.
+    inline int readdir_at(const char* path, const char** names, int max, int startIndex) {
+        return (int)syscall4(Montauk::SYS_READDIR_AT, (uint64_t)path, (uint64_t)names,
+                             (uint64_t)max, (uint64_t)startIndex);
+    }
 
     // File write/create
     inline int fwrite(int handle, const uint8_t* buf, uint64_t off, uint64_t size) {