feat(hw): #58 nomarchy-detect-hw post-install re-probe CLI

Package the installer’s pure hardware-db probe as nomarchy-detect-hw:
prints suggested hardwareProfile and system.nix snippets (or --raw
protocol lines). Does not rewrite the flake. On PATH via the distro
module; docs/HARDWARE.md §8 updated. Close #58.

Verified: V1 (build + run on AMD laptop with fingerprint/NPU/IR cam).

pkgs/nomarchy-detect-hw/default.nix

@@ -0,0 +1,43 @@
+# Post-install hardware re-probe (BACKLOG #58 / HARDWARE.md §8).
+# Same pure nomarchy_detect_hw protocol as the installer; prints suggested
+# hardwareProfile + system.nix snippets. Never rewrites the flake.
+{ lib
+, stdenvNoCC
+, makeWrapper
+, bash
+, coreutils
+, pciutils
+, usbutils
+, util-linux
+}:
+
+stdenvNoCC.mkDerivation {
+  pname = "nomarchy-detect-hw";
+  version = "0.1.0";
+
+  src = ./.;
+
+  nativeBuildInputs = [ makeWrapper ];
+
+  installPhase = ''
+    runHook preInstall
+
+    share=$out/share/nomarchy-detect-hw
+    install -Dm644 ${../nomarchy-install/hardware-db.sh} "$share/hardware-db.sh"
+    install -Dm755 nomarchy-detect-hw.sh $out/bin/nomarchy-detect-hw
+    patchShebangs $out/bin/nomarchy-detect-hw
+
+    wrapProgram $out/bin/nomarchy-detect-hw \
+      --prefix PATH : ${lib.makeBinPath [ bash coreutils pciutils usbutils util-linux ]} \
+      --set NOMARCHY_DETECT_HW_SHARE "$share"
+
+    runHook postInstall
+  '';
+
+  meta = {
+    description = "Probe hardware and print Nomarchy hardwareProfile / system.nix suggestions";
+    license = lib.licenses.mit;
+    mainProgram = "nomarchy-detect-hw";
+    platforms = lib.platforms.linux;
+  };
+}