catpaq integration

I’m developing an official open-source GUI for zpaqfranz (and ZPAQ archives in general)
https://github.com/fcorbelli/catpaq
It is an evolution of my previous project PAKKA (a 32-bit Delphi program), now rewritten in Lazarus.
The UI is very basic (it looks like a 30-year-old NextStep program), but it has a major advantage:
the exact same source compiles “first time” on Windows, macOS (Intel & ARM), and Linux, providing the long-awaited GUI.
It’s currently in an embryonic state—more a tech demo than usable software.
Still, initial builds for macOS and Linux have succeeded.
The main Linux challenge is the wide variety of GTK library versions across distributions.
It won’t be easy, but it’s feasible.

DLL version implemented

zpaqfranz.exe can now be built as zpaqfranz.dll
(using the -DDLL flag).
This mode is intended as a fast interface for the new portable official catpaq GUI
to reduce data transfer times.
In the future (maybe), I might do something similar for macOS and Linux.

-catpaq

This flag enables feedback mode for catpaq,
primarily used to update progress bars in the GUI.

FRANZEN 4

I implemented a variant of FRANZEN called FRENZEN (naming isn’t my strong suit).
This format marks files encrypted with both FRANZEN and AES,
making it easier and more robust to detect different modes.

Reminder: FRANZEN is highly experimental,

and backward compatibility with previous versions is NOT guaranteed.
We are close; password handling needs further work, but
this is less demanding code-wise than the full implementation.

Minor fixes

Some small but annoying bugs were fixed.
Thanks to https://github.com/cheebusjeebus for reporting one of the smallest yet worst issues (missing % sign).