make usb.vhd if missing, fix clear behavior

code/build/build.c

@@ -71,16 +71,45 @@ Nob_Proc run_async(const char *cmd_str) {
     return proc;
 }
 
+// Creates an empty USB image the first time the build sees a missing usb.vhd.
+// The image is intentionally left unmounted and unpopulated after formatting so
+// callers can use it as removable FAT32 storage without the build overwriting it.
+bool create_usb_vhd_if_missing(void) {
+    if (nob_file_exists("usb.vhd")) return true;
+
+    char vhd_path[MAX_PATH];
+    GetFullPathNameA("usb.vhd", MAX_PATH, vhd_path, NULL);
+
+    const char *diskpart_script = nob_temp_sprintf(
+        "create vdisk file=\"%s\" maximum=256 type=fixed\n"
+        "select vdisk file=\"%s\"\n"
+        "attach vdisk\n"
+        "convert gpt\n"
+        "create partition primary\n"
+        "format fs=fat32 quick\n"
+        "detach vdisk\n"
+        "exit\n",
+        vhd_path, vhd_path
+    );
+
+    nob_log(NOB_INFO, "usb.vhd missing, creating empty 256 MB FAT32 GPT image...");
+    nob_write_entire_file("usb_mkimage.txt", diskpart_script, strlen(diskpart_script));
+    bool ok = run_sync("diskpart /s usb_mkimage.txt");
+    remove("usb_mkimage.txt");
+    return ok;
+}
+
 // Runs the requested operation.
 int main(int argc, char **argv) {
     // The build tool rebuilds itself before doing any real work so the graph below matches the source.
     NOB_GO_REBUILD_URSELF(argc, argv);
 
-    // The disk image must exist before the build can copy fresh binaries into it.
+    // The boot image must exist before the build can copy fresh binaries into it.
     if (!nob_file_exists("disk.vhd")) {
         nob_log(NOB_INFO, "disk.vhd missing, calling mkimage.bat...");
         if (!run_sync("mkimage.bat")) return 1;
     }
+    if (!create_usb_vhd_if_missing()) return 1;
     create_layout();
 
     // Core images build sequentially because later images link against earlier import libraries.

code/kernel/ke_display.c

@@ -677,8 +677,11 @@ static KSTATUS KiDisplayClearLocked(uint32_t color) {
         return s;
     KiDisplayBeginDraw();
     s = KiDisplayFillRectNoCursor(0, 0, (int)mode.Width, (int)mode.Height, color);
-    if (KSUCCESS(s))
+    if (KSUCCESS(s)) {
         KiDisplayConsoleResetCellsLocked();
+        gConsoleX = 0;
+        gConsoleY = 0;
+    }
     KSTATUS ps = KiDisplayEndDraw();
     return KSUCCESS(s) ? ps : s;
 }