feat(ci): expose guest-cpu/guest-memory-mb; ns7zip Linux 8GB

job.py already patches the clone VMX (numvcpus/memsize) via
--guest-cpu/--guest-memory-mb; expose them as action inputs
(default '0' = keep template). build-ns7zip.yml sets
guest-memory-mb: 8192 — the parallel MinGW cross-compile thrashes at
the 4 GB Linux template default (Windows template is 6 GB).

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

.gitea/workflows/build-ns7zip.yml

@@ -46,6 +46,10 @@ jobs:
           # Cross-repo build: github.ref_name is this repo's branch, not
           # nsis-plugin-ns7zip's. Pin the target repo's branch.
           repo-branch:     'main'
+          # 8 GB: the parallel MinGW cross-compile thrashes at the 4 GB
+          # Linux template default (3 concurrent make -j). Harmless for
+          # Windows (host has ample RAM).
+          guest-memory-mb: '8192'
           # Suffix disambiguates artifact dirs: F:\CI\Artifacts\{run_id}-{attempt}-windows
           job-id-suffix:   '${{ matrix.target }}'
           artifact-name:   'nsis-plugin-ns7zip-${{ matrix.target }}-${{ github.ref_name }}'