build: rebrand user-visible display strings in modsrc

Patch additional user-facing strings in the Ventoy modsrc:
- 'Ventoy grub is not launched by Ventoy shim' -> 'Hiperiso...'
- 'standard Ventoy device' -> 'standard Hiperiso device'
- 'Ventoy scanning files' -> 'Hiperiso scanning files'
- 'Ventoy Secure Policy' -> 'Hiperiso Secure Policy'
- 'ventoy not ready' -> 'hiperiso not ready'

These are the only display strings a user sees in the GRUB module.
Internal symbol/function/variable names (g_ventoy_*, ventoy_*)
are kept as-is since they're part of the disk format and must
match for compatibility with the chain boot path.

QEMU test confirms GRUB boots cleanly from a test disk built
with this patched modsrc + the ESP image at sector 458752.

scripts/build_grub2_204.sh

@@ -43,6 +43,11 @@ find "$BUILD_DIR/SRC/grub-2.04/grub-core/ventoy" -type f \
      -e 's|admin@ventoy\.net|adminpupkin@gmail.com|g' \
      -e 's|longpanda|vasilito|g' \
      -e 's|to use Ventoy|to use Hiperiso|g' \
+     -e 's|Ventoy grub is not launched by Ventoy shim|Hiperiso grub is not launched by Hiperiso shim|g' \
+     -e 's|standard Ventoy device|standard Hiperiso device|g' \
+     -e 's| Ventoy scanning files| Hiperiso scanning files|g' \
+     -e 's|Ventoy Secure Policy|Hiperiso Secure Policy|g' \
+     -e 's|grub_printf("ventoy not ready|grub_printf("hiperiso not ready|g' \
      {} +
 
 cp "$HIPERISO_ROOT/src/grub2/grub/grub.cfg" "$SRC_DIR/"