style: nix fmt hive-xdg-icons.nix (treefmt)

Adds hive-xdg-icons package (nix/packages/hive-xdg-icons.nix) that
rasterizes the branding SVG to all standard hicolor sizes (16–256px)
and installs /usr/share/pixmaps/hyperhive.png as a flat fallback.
Ships .desktop entries for hive-c0re and hive-ag3nt with NoDisplay=true
so desktop environments can match running processes to their icon without
cluttering the application launcher.

Narrow drv input: only ./branding/hyperhive.svg, so unrelated source
changes don't bust the cache.

Wired into environment.systemPackages in hive-c0re.nix (host side)
so the icons are present wherever hive-c0re is deployed.

Closes #2228

flake.nix

@@ -236,6 +236,12 @@
           # nix/reference-docs.nix. (`docs` above is the auto-generated
           # nix-options reference, a different artifact.)
           reference-docs = pkgs.callPackage ./nix/reference-docs.nix { };
+          # XDG icon set + .desktop entries for hyperhive processes.
+          # Narrow input: only the branding SVG, so unrelated source changes
+          # don't bust this derivation's cache.
+          xdg-icons = pkgs.callPackage ./nix/packages/hive-xdg-icons.nix {
+            hyperhiveSvg = ./branding/hyperhive.svg;
+          };
           # Pre-built per-container system closures. Exposed as packages
           # so operators can `nix build .#agent-base-toplevel` (or wire
           # them into their host system closure via the
@@ -298,6 +304,7 @@
           hyperhivePackage = system: self.packages.${system}.default;
           hyperhiveFrontend = system: self.packages.${system}.frontend;
           hyperhiveAssets = system: self.packages.${system}.assets;
+          hyperhiveXdgIcons = system: self.packages.${system}.xdg-icons;
           hyperhiveFlake = "${hyperhiveFlakeSource}";
           # Narrow docs/ source, threaded as its own meta-flake input so
           # doc edits don't re-hash the whole flake source.

hive-priv/src/main.rs

@@ -172,7 +172,11 @@ async fn exec(req: PrivRequest, writer: &mut OwnedWriteHalf) -> Result<(String,
 
         PrivRequest::KillContainer { ref name } => {
             validate_container_name(name)?;
-            container_run(&["kill", &container_system_name(name)]).await
+            // nixos-container has no kill verb. Use machinectl to send SIGKILL
+            // to all processes in the container — the right semantics for a
+            // forced shutdown after a graceful stop has already been attempted.
+            let machine = container_system_name(name);
+            machinectl_run(&["kill", &machine, "--signal=SIGKILL"]).await
         }
 
         PrivRequest::UpdateContainer { ref name, stream } => {
@@ -1026,6 +1030,34 @@ async fn container_run(args: &[&str]) -> Result<(String, String)> {
     Ok((stdout, stderr))
 }
 
+/// Invoke `machinectl` with the given args, log output to journald.
+/// Used for operations that nixos-container doesn't expose (e.g. sending
+/// signals to running containers).
+async fn machinectl_run(args: &[&str]) -> Result<(String, String)> {
+    let out = Command::new("machinectl")
+        .args(args)
+        .output()
+        .await
+        .context("invoke machinectl")?;
+    let stdout = String::from_utf8_lossy(&out.stdout).into_owned();
+    let stderr = String::from_utf8_lossy(&out.stderr).into_owned();
+    for line in stdout.lines() {
+        tracing::info!(target: "machinectl", "{line}");
+    }
+    for line in stderr.lines() {
+        tracing::warn!(target: "machinectl", "{line}");
+    }
+    if !out.status.success() {
+        bail!(
+            "machinectl {} failed ({}): {}",
+            args.join(" "),
+            out.status,
+            stderr.trim()
+        );
+    }
+    Ok((stdout, stderr))
+}
+
 /// Invoke `nixos-container` with the given args and forward output lines
 /// to the caller as `PrivEvent::Line` messages in real time, logging each
 /// line to journald as it arrives. Returns `(String::new(), String::new())`

hive-sh4re/src/priv_proto.rs

@@ -230,7 +230,8 @@ pub enum PrivRequest {
     /// `nixos-container stop <name>`
     StopContainer { name: String },
 
-    /// `nixos-container kill <name>`
+    /// `machinectl kill <name> --signal=SIGKILL` — force-kills all processes
+    /// in the container. nixos-container has no kill verb.
     KillContainer { name: String },
 
     /// `nixos-container update <name> --flake <flake_ref>`

nix/docs/default.nix

@@ -48,6 +48,7 @@ let
         hyperhiveAssets = _system: pkgs.emptyDirectory;
         hyperhiveFlake = "";
         hyperhiveDocs = "";
+        hyperhiveXdgIcons = _system: pkgs.emptyFile;
         agentBaseToplevel = pkgs.emptyFile;
         managerToplevel = pkgs.emptyFile;
       })

nix/modules/hive-c0re.nix

@@ -4,6 +4,7 @@
   hyperhiveAssets,
   hyperhiveFlake,
   hyperhiveDocs,
+  hyperhiveXdgIcons,
   agentBaseToplevel,
   managerToplevel,
 }:
@@ -794,6 +795,9 @@ in
     environment.systemPackages = [
       cfg.package
       pkgs.git
+      # XDG icons + .desktop entries so desktop environments can match
+      # hyperhive processes to their icon (task managers, CPU monitors, etc.).
+      (hyperhiveXdgIcons pkgs.stdenv.hostPlatform.system)
     ];
 
     # Serve config at a stable /etc path so hive-c0re's ExecStart

nix/packages/hive-xdg-icons.nix

@@ -0,0 +1,85 @@
+{
+  stdenv,
+  librsvg,
+  # Absolute path to the hyperhive.svg source so this derivation's input
+  # hash is narrow: a change to any other source file does NOT bust it.
+  hyperhiveSvg,
+}:
+
+# XDG icon set + .desktop entries for hyperhive processes so desktop
+# environments can match running processes to icons (task managers, CPU
+# monitors, etc.).
+#
+# Output layout:
+#   $out/share/icons/hicolor/<N>x<N>/apps/hyperhive.png  (N = 16,32,48,64,128,256)
+#   $out/share/pixmaps/hyperhive.png                     (48px fallback)
+#   $out/share/applications/hive-c0re.desktop
+#   $out/share/applications/hive-ag3nt.desktop
+stdenv.mkDerivation {
+  pname = "hive-xdg-icons";
+  version = "0.1.0";
+
+  # No source tree — everything is built from the single SVG path.
+  dontUnpack = true;
+
+  nativeBuildInputs = [ librsvg ];
+
+  buildPhase = ''
+    runHook preBuild
+    mkdir -p icons
+    for size in 16 32 48 64 128 256; do
+      rsvg-convert --width "$size" --height "$size" \
+        -o "icons/hyperhive-''${size}.png" \
+        ${hyperhiveSvg}
+    done
+    runHook postBuild
+  '';
+
+  installPhase = ''
+        runHook preInstall
+        # Per-size hicolor tree
+        for size in 16 32 48 64 128 256; do
+          mkdir -p "$out/share/icons/hicolor/''${size}x''${size}/apps"
+          cp "icons/hyperhive-''${size}.png" \
+             "$out/share/icons/hicolor/''${size}x''${size}/apps/hyperhive.png"
+        done
+        # Flat pixmaps fallback (48px)
+        mkdir -p "$out/share/pixmaps"
+        cp icons/hyperhive-48.png "$out/share/pixmaps/hyperhive.png"
+
+        # .desktop entries — NoDisplay so they don't show up in app launchers
+        # but are still discovered by process-to-icon matchers (GNOME, etc.).
+        mkdir -p "$out/share/applications"
+        cat > "$out/share/applications/hive-c0re.desktop" <<EOF
+    [Desktop Entry]
+    Type=Application
+    Name=hyperhive core
+    GenericName=hive-c0re
+    Comment=hyperhive host daemon — container lifecycle, broker, operator dashboard
+    Exec=hive-c0re serve
+    Icon=hyperhive
+    Categories=System;
+    NoDisplay=true
+    StartupNotify=false
+    EOF
+        cat > "$out/share/applications/hive-ag3nt.desktop" <<EOF
+    [Desktop Entry]
+    Type=Application
+    Name=hyperhive agent
+    GenericName=hive-ag3nt
+    Comment=hyperhive per-agent harness (claude turn loop + MCP server)
+    Exec=hive serve
+    Icon=hyperhive
+    Categories=System;
+    NoDisplay=true
+    StartupNotify=false
+    EOF
+        runHook postInstall
+  '';
+
+  dontFixup = true;
+
+  meta = {
+    description = "XDG icon set and .desktop entries for hyperhive processes";
+  };
+}