fix(rpm): rename neuron package to helexa-neuron

Fedora's official repos ship a package named `neuron` — the NEURON
neural-simulation environment from Yale (see
https://src.fedoraproject.org/rpms/neuron). Having our own `neuron`
in the helexa COPR caused dnf5 to silently no-op `dnf install neuron`
because of the name collision, even with the COPR repo enabled and
keys imported. The only workarounds were full NEVRA (`dnf install
neuron-0.1.12-1.fc43.x86_64`) or a local file install — neither
acceptable for end-users.

Rename the RPM package to `helexa-neuron`. Keep binary (/usr/bin/neuron),
systemd unit (neuron.service), system user (neuron), and config dir
(/etc/neuron) unchanged — those are project-local contexts where the
short name is unambiguous. Follows Fedora subpackage-style naming
except with a vendor prefix rather than a parent-package prefix,
because neuron is an independent package from cortex (installed on
different hosts) and neither depends on the other.

Changes:
- neuron.spec -> helexa-neuron.spec (git rename)
- Name: neuron -> helexa-neuron (with comment explaining why)
- CI: srpm-neuron job now builds helexa-neuron-VERSION.tar.gz with the
  matching top-level dir prefix, publishes to helexa/helexa-neuron COPR
- CI: bump-version job references helexa-neuron.spec
- CLAUDE.md: install instructions updated

Old helexa/neuron COPR project can be deleted after the first
helexa/helexa-neuron build lands.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

helexa-neuron.spec

@@ -0,0 +1,87 @@
+Name:           helexa-neuron
+Version:        0.1.12
+Release:        1%{?dist}
+Summary:        Per-node GPU discovery and harness management daemon for cortex
+# Package name disambiguates from Fedora's existing "neuron" package
+# (NEURON neural simulation environment from Yale). Binary, systemd
+# unit, and system user are still called "neuron" for brevity.
+
+License:        GPL-3.0-or-later
+URL:            https://git.lair.cafe/helexa/cortex
+Source0:        %{name}-%{version}.tar.gz
+Source1:        %{name}-%{version}-vendor.tar.gz
+
+ExclusiveArch:  x86_64
+
+BuildRequires:  rust >= 1.85
+BuildRequires:  cargo
+BuildRequires:  gcc
+BuildRequires:  gcc-c++
+BuildRequires:  cmake
+BuildRequires:  perl-interpreter
+BuildRequires:  pkgconfig(openssl)
+BuildRequires:  systemd-rpm-macros
+
+Requires(pre):  shadow-utils
+Requires:       systemd
+
+# systemd-rpm-macros ships a unit dep generator that parses User=/Group=
+# from our .service file and emits Requires: user(neuron)/group(neuron).
+# rpm's sysusers provides-generator emits the unversioned form for groups
+# but only a versioned user(neuron) = <base64> for users with GECOS/home/
+# shell. Provide the unversioned user(neuron) explicitly so dnf can resolve
+# the auto-generated Requires. Without this, dnf5 silently filters the
+# package and reports "Nothing to do".
+Provides:       user(neuron)
+
+%description
+Neuron is a per-node daemon for cortex inference clusters. It discovers
+local GPU hardware via nvidia-smi, manages inference harnesses (mistral.rs,
+llama.cpp), and exposes an HTTP API for model lifecycle management.
+
+%prep
+%autosetup
+tar xf %{SOURCE1}
+mkdir -p .cargo
+cat > .cargo/config.toml << 'EOF'
+[source.crates-io]
+replace-with = "vendored-sources"
+
+[source.vendored-sources]
+directory = "vendor"
+EOF
+
+%build
+cargo build --release -p neuron
+
+%install
+install -Dm755 target/release/neuron %{buildroot}%{_bindir}/neuron
+install -Dm644 data/neuron.service %{buildroot}%{_unitdir}/neuron.service
+install -Dm644 data/neuron-sysusers.conf %{buildroot}%{_sysusersdir}/neuron.conf
+install -dm755 %{buildroot}%{_sysconfdir}/neuron
+install -Dm644 neuron.example.toml %{buildroot}%{_sysconfdir}/neuron/neuron.toml
+
+%pre
+%sysusers_create_compat %{_builddir}/%{name}-%{version}/data/neuron-sysusers.conf
+
+%post
+%systemd_post neuron.service
+
+%preun
+%systemd_preun neuron.service
+
+%postun
+%systemd_postun_with_restart neuron.service
+
+%files
+%license LICENSE
+%doc README.md
+%{_bindir}/neuron
+%{_unitdir}/neuron.service
+%{_sysusersdir}/neuron.conf
+%dir %{_sysconfdir}/neuron
+%config(noreplace) %{_sysconfdir}/neuron/neuron.toml
+
+%changelog
+* Wed Apr 15 2026 Rob Thijssen <grenade@rob.tn> - 0.1.0-1
+- Initial package