fix(ci): correct ns7zip build-command and artifact-source

build_plugin.py is a dispatcher: it auto-detects host/toolset and
forwards extra args to the per-version script, which rejected
--final/--dist-dir. Both the Windows (legacy 2601_vs2026) and Linux
build scripts copy nsis7z.dll into <repo>/plugins/{x86-ansi,
x86-unicode,amd64-unicode}, not dist.

- build-command: just `python build_plugin.py` (python3 on Linux —
  Ubuntu 24.04 has no `python`).
- artifact-source: 'plugins' (fixes the "dist missing" failure too).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.gitea/workflows/build-ns7zip.yml

@@ -27,8 +27,13 @@ jobs:
     steps:
       - uses: https://gitea.emulab.it/Simone/local-ci-cd-system/.gitea/actions/local-ci-build@main
         with:
-          build-command:   'python build_plugin.py --final --dist-dir dist'
+          # build_plugin.py auto-detects host/toolset and builds all
-          artifact-source: 'dist'
+          # configs by default; --final/--dist-dir do not exist (they were
+          # forwarded to the per-version script and rejected). Output DLLs
+          # are copied to <repo>/plugins/{x86-ansi,x86-unicode,amd64-unicode}.
+          # Ubuntu 24.04 has no `python`, use `python3` on the Linux leg.
+          build-command:   ${{ matrix.target == 'linux' && 'python3 build_plugin.py' || 'python build_plugin.py' }}
+          artifact-source: 'plugins'
           submodules:      'true'
           guest-os:        ${{ matrix.target == 'linux' && 'Linux' || 'Windows' }}
           # repo-url uses the host SSH alias `gitea-ci` (~/.ssh/config),