docs: complete zupt → vaptvupt rename; README v4.0.0 refresh

- README: add 'What's new in 4.0.0' section, extend release history
  v2.2.4 → v4.0.0, fix stale section titles (benchmark/security/feature
  tables), point fast-install at short.securityops.co/vaptvupt, fix
  related-project links (vaptvupt-codec, libvuptsdk, real repo names)
- install.sh: clone the renamed repo, vaptvupt success message
- Rename remaining zupt → vaptvupt across INSTALL.md, DISTRIBUTION.md,
  SECURITY.md, THREAT_MODEL.md, ROADMAP.md, THIRD-PARTY-NOTICES.md,
  gui/ + sdk/ + packaging READMEs, doc/vaptvupt.1, spec comments/URLs
- New doc/vaptvupt-gui.1 (GUI 1.3.0, VAPTVUPT_BIN/ZUPT_BIN env vars);
  doc/zupt-gui.1 kept as hardlinked compat copy
- Deliberately unchanged: .zupt extension, ZUPT header magic,
  ZUPT-* crypto domain-separation constants, zupt_*/ZUPT_* code
  identifiers, libzuptsdk artifact names, legacy symlink notes,
  CHANGELOG/AUDIT historical entries, Provides/Obsoletes upgrade path
- tests/test_packaging_syntax.sh: THREAT_MODEL section titles updated

doc/zupt-gui.1

@@ -1,13 +1,16 @@
-.TH ZUPT-GUI 1 "2026-04-27" "zupt-gui 1.1.1" "User Commands"
+.\" Manpage for vaptvupt-gui (formerly zupt-gui; INPI Brasil trademark rename in v3.0.0)
+.\" SPDX-License-Identifier: AGPL-3.0-or-later
+.\" Copyright (c) 2025-2026 Cristian Cezar Moisés
+.TH VAPTVUPT-GUI 1 "2026-06-11" "vaptvupt-gui 1.3.0" "User Commands"
 .SH NAME
-zupt-gui \- graphical interface for the Zupt post-quantum backup utility
+vaptvupt-gui \- graphical interface for the VaptVupt post-quantum backup utility
 .SH SYNOPSIS
-.B zupt-gui
+.B vaptvupt-gui
 .RI [ ARCHIVE ]
 .SH DESCRIPTION
-.B zupt-gui
+.B vaptvupt-gui
 is a graphical frontend for
-.BR zupt (1).
+.BR vaptvupt (1).
 It provides tabs for compression, extraction, key management, and
 full-disk backup. Both PQ encryption modes are exposed:
 .B legacy --pq
@@ -15,12 +18,17 @@ and
 .B SDK v2 --pq-sdk
 (HKDF combiner, key commitment, HPKE binding, Argon2id).
 
+The legacy command name
+.B zupt-gui
+is preserved as a symlink for backward compatibility; both invocations
+behave identically.
+
 If
 .I ARCHIVE
 is given on the command line, the GUI opens directly on the
 extract tab with that archive preloaded.
 
-.B zupt-gui
+.B vaptvupt-gui
 uses Qt 6. It works with either of the following Python Qt bindings,
 auto-detected at startup in this order:
 .IP \(bu 2
@@ -46,13 +54,13 @@ and/or PQ private key.
 Generate ML-KEM-768 + X25519 keypair. The
 .B SDK v2 format
 checkbox controls whether the keypair is generated via
-.B zupt keygen --sdk
+.B vaptvupt keygen --sdk
 (producing
 .IR file
 and
 .IR file.pub
 in one step) or via the legacy
-.BR "zupt keygen" .
+.BR "vaptvupt keygen" .
 .TP
 .B Disk
 Full-disk backup and restore. Enumerates block devices with
@@ -60,29 +68,39 @@ human-readable sizes. Same encryption mode controls as Compress.
 
 .SH FILES
 .TP
-.I /usr/bin/zupt-gui
-Wrapper script that invokes the Python entry point.
+.I /usr/bin/vaptvupt-gui
+Wrapper script that invokes the Python entry point (and the symlinked
+legacy
+.IR /usr/bin/zupt-gui ).
 .TP
-.I /usr/lib/zupt-gui/zupt_gui.py
+.I /usr/lib/vaptvupt-gui/zupt_gui.py
 Main Python source.
 .TP
-.I /usr/share/applications/zupt-gui.desktop
+.I /usr/share/applications/vaptvupt-gui.desktop
 Desktop entry for menu integration.
 .TP
-.I /usr/share/icons/hicolor/256x256/apps/zupt-gui.png
+.I /usr/share/icons/hicolor/256x256/apps/vaptvupt-gui.png
 Application icon.
 
 .SH ENVIRONMENT
 .TP
-.B ZUPT_BINARY
+.B VAPTVUPT_BIN
 Override the path to the
-.B zupt
+.B vaptvupt
 binary (default: search
 .IR PATH ).
+The legacy name
+.B ZUPT_BIN
+is also honoured.
+.TP
+.B VAPTVUPT_DEBUG
+Enable binary-discovery debug logging on stderr. The legacy name
+.B ZUPT_DEBUG
+is also honoured.
 
 .SH BUGS
 Report at
-.UR https://git.securityops.co/cristiancmoises/zupt/issues
+.UR https://git.securityops.co/cristiancmoises/vaptvupt/issues
 .UE .
 
 .SH AUTHOR
@@ -91,11 +109,11 @@ Cristian Cezar Moisés
 .ME
 
 .SH SEE ALSO
-.BR zupt (1).
+.BR vaptvupt (1).
 
 .SH LICENSE
 .PP
-zupt-gui is licensed under the
+vaptvupt-gui is licensed under the
 .B GNU Affero General Public License version 3 or later
 (AGPL-3.0-or-later). Commercial license available for relief from
 copyleft terms; contact
@@ -105,5 +123,5 @@ copyleft terms; contact
 .SH PROJECT
 .PP
 Home page:
-.UR https://git.securityops.co/cristiancmoises/zupt
+.UR https://git.securityops.co/cristiancmoises/vaptvupt
 .UE