cmd: remove hpkg

This proof-of-concept was abandoned long ago. Its test suite is flaky, heavy on I/O and does not increase test coverage. This change fully removes hpkg and supporting code.

Signed-off-by: Ophestra <cat@gensokyo.uk>

.gitea/workflows/test.yml

@@ -89,23 +89,6 @@ jobs:
           path: result/*
           retention-days: 1
 
-  hpkg:
-    name: Hpkg
-    runs-on: nix
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v4
-
-      - name: Run NixOS test
-        run: nix build --out-link "result" --print-out-paths --print-build-logs .#checks.x86_64-linux.hpkg
-
-      - name: Upload test output
-        uses: actions/upload-artifact@v3
-        with:
-          name: "hpkg-vm-output"
-          path: result/*
-          retention-days: 1
-
   check:
     name: Flake checks
     needs:
@@ -114,7 +97,6 @@ jobs:
       - sandbox
       - sandbox-race
       - sharefs
-      - hpkg
     runs-on: nix
     steps:
       - name: Checkout