legal: bundle third-party licenses on the ISO; stop shipping doom1.wad

- New 0:/os/licenses/ directory on the ISO with GPL-3.0.txt (Flat Remix
  icon theme), GPL-2.0.txt (doomgeneric DOOM engine), and NOTICES.txt
  (mirrors montaukos.org/THIRD-PARTY-NOTICES.txt).
- THIRD-PARTY-NOTICES.txt gains a Flat Remix section (GPLv3, attribution,
  modification and corresponding-source statements; the shipped SVGs are
  the source form).
- man legal now lists third-party components and points at 0:/os/licenses/.
- doom1.wad removed from the repo and the build: the shareware WAD is
  proprietary id Software content. doom.elf (GPLv2) still ships; users
  must supply their own WAD.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

montaukos.org/THIRD-PARTY-NOTICES.txt

@@ -138,24 +138,55 @@ License: GNU General Public License, version 2 (GPLv2)
   IMPORTANT: The DOOM application (doom.elf) is licensed under GPLv2, separately
   from MontaukOS itself. The MontaukOS Software License Agreement does NOT apply
   to doom.elf or to the doomgeneric/DOOM source. The full GPLv2 license text is
-  distributed with the corresponding source.
+  included on the MontaukOS ISO at 0:/os/licenses/GPL-2.0.txt.
 
   WRITTEN OFFER FOR SOURCE: The complete corresponding source code for the DOOM
   application, under the terms of GPLv2, is available on request and is provided
   alongside MontaukOS distributions. Contact: daniel@nexlink.cloud.
 
-  DOOM GAME DATA (doom1.wad): This notice and the GPLv2 license cover only the
-  DOOM engine code, NOT the DOOM game data. MontaukOS bundles "doom1.wad", the
-  DOOM shareware episode (Knee-Deep in the Dead), which is Copyright (C) id
-  Software, Inc. The shareware WAD is NOT covered by the GPL and is NOT public
-  domain. id Software's shareware terms permit free, non-commercial redistribution
-  of the unmodified shareware WAD, but do not grant rights for commercial
-  distribution or modification. If MontaukOS is ever distributed commercially, the
-  shareware WAD should be removed and replaced with a freely licensed alternative
-  (e.g. the Freedoom project's freedoom1.wad / freedoom2.wad, released under a
-  BSD-style license), or distributed only with id Software's permission. The
-  registered/commercial DOOM WADs (e.g. doom.wad, doom2.wad) are separate
-  copyrighted assets and are NOT distributed with MontaukOS.
+  DOOM GAME DATA: This notice and the GPLv2 license cover only the DOOM engine
+  code, NOT any DOOM game data. MontaukOS does NOT distribute any DOOM WAD files;
+  they are proprietary content of id Software, Inc. To play, users must supply
+  their own legally obtained WAD, or a freely licensed alternative such as the
+  Freedoom project's freedoom1.wad / freedoom2.wad (BSD-style license).
+
+
+================================================================================
+5. Flat Remix (icon theme)
+================================================================================
+The MontaukOS desktop and applications use icons from the Flat Remix icon theme
+by Daniel Ruiz de Alegria. MontaukOS ships a curated subset of the theme
+(renamed and reorganized for MontaukOS) in SVG form on the ISO (0:/icons/ and
+per-application icon files).
+
+  Copyright (C) Daniel Ruiz de Alegria <daniel@drasite.com>
+  Upstream: https://github.com/daniruiz/flat-remix
+
+License: GNU General Public License, version 3 (GPLv3)
+
+  Flat Remix is free software: you can redistribute it and/or modify it under
+  the terms of the GNU General Public License as published by the Free Software
+  Foundation, either version 3 of the License, or (at your option) any later
+  version.
+
+  This program is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+  FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+  IMPORTANT: The Flat Remix icons are licensed under GPLv3, separately from
+  MontaukOS itself. The MontaukOS Software License Agreement does NOT apply to
+  the icon files, which remain under GPLv3. The full GPLv3 license text is
+  included on the MontaukOS ISO at 0:/os/licenses/GPL-3.0.txt.
+
+  MODIFICATIONS: The icons shipped with MontaukOS are a modified subset of Flat
+  Remix (files selected, renamed, and reorganized for MontaukOS; first modified
+  2025). These modified versions are likewise available under GPLv3.
+
+  CORRESPONDING SOURCE: The icons are distributed in SVG form, which is their
+  source (preferred form for modification); the files on the ISO are the
+  corresponding source. The complete unmodified theme is available from the
+  upstream repository above, and the MontaukOS-modified set is available on
+  request: daniel@nexlink.cloud.
 
 
 ================================================================================