Judge tests that read another repository against what the check clones, never the desktop's checkout (issue 432)

Tests that read ../../../mesh-catalog or ../../../mesh-host gave a verdict
that depended on what sat beside the checkout: a stale or dirty sibling
failed them on a desktop, and a missing one skipped them unseen. They now
read the clone the build seat puts in MESH_CHECK_BESIDE, failing when it is
absent there, and elsewhere a copy captured at a named commit.

The skip had hidden that the builder test read a module retired by ADR 0190.
The systemd reading test no longer counts the machine's own environment.d.

testdata/beside/mesh-catalog/modules/clipmenu/module.json.captured

@@ -0,0 +1,81 @@
+{
+  "module": "clipmenu",
+  "version": "1",
+  "capabilities": [
+    "package-manager"
+  ],
+  "requires": [
+    "x11-display"
+  ],
+  "claims": [
+    {
+      "name": "node-clipboard",
+      "scope": "node",
+      "serves": [
+        "history",
+        "copy"
+      ]
+    }
+  ],
+  "tools": [
+    "clipmenu_paste",
+    "clipmenu_clear",
+    "clipmenu_delete"
+  ],
+  "environment": {
+    "variables": {
+      "CM_SELECTIONS": "clipboard",
+      "CM_MAX_CLIPS": "500",
+      "CM_HISTLENGTH": "15"
+    }
+  },
+  "shell": [
+    {
+      "for": "xinitrc",
+      "slot": "normal",
+      "code": "# The clipboard's history (module clipmenu, novox/hq ADR 0208): clipmenud collects every copy from\n# here on, once per session. It keeps the history in the account's runtime directory, so a reboot\n# forgets it, and with it every password that was ever copied.\n# Through the module's xsel, which reads only a selection offering text (see the README).\nPATH=\"/usr/local/lib/mesh-clipmenu:$PATH\" clipmenud &\n"
+    }
+  ],
+  "resources": [
+    {
+      "id": "package",
+      "type": "package",
+      "package": "clipmenu"
+    },
+    {
+      "id": "greenclip",
+      "type": "package",
+      "package": "rofi-greenclip",
+      "absent": true
+    },
+    {
+      "id": "text-only",
+      "type": "file",
+      "path": "/usr/local/lib/mesh-clipmenu/xsel",
+      "mode": "0755",
+      "content": "#!/bin/sh\n# xsel as clipmenud sees it, written by the mesh (module clipmenu). Replaced at every push.\n#\n# clipmenud records text, and reads a selection with `timeout 1 xsel -o`. A selection holding an\n# image (a screenshot copied as image/png) is sent in pieces; one second is too short for megabytes,\n# timeout kills xsel half way, and the program owning the image waits for ever for a reader that is\n# gone. From then on nothing can ask the clipboard anything: pastes hang, and an Electron app that\n# asks on its main thread freezes. So a read goes ahead only when the selection offers text.\ncase \" $* \" in\n*\" -o \"* | *\" --output \"*)\n\tselection=clipboard\n\tcase \" $* \" in\n\t*\" --primary \"* | *\" -p \"*) selection=primary ;;\n\t*\" --secondary \"* | *\" -s \"*) selection=secondary ;;\n\tesac\n\ttargets=$(timeout 1 xclip -selection \"$selection\" -t TARGETS -o 2>/dev/null) || exit 1\n\tprintf '%s\\n' \"$targets\" | grep -qxE 'UTF8_STRING|STRING|TEXT|text/plain(;charset=utf-8)?' || exit 1\n\t;;\nesac\nexec /usr/bin/xsel \"$@\"\n"
+    }
+  ],
+  "build": {
+    "artifacts": [
+      {
+        "name": "tools",
+        "kind": "bundle",
+        "language": "go",
+        "system": "arch",
+        "from": "cmd/clipmenu-tools",
+        "binary": "clipmenu-tools",
+        "loads": [
+          "clipmenu-tools"
+        ]
+      }
+    ]
+  },
+  "contributions": [
+    {
+      "seat": "node-display-session",
+      "kind": "config",
+      "content": "# The clipboard's history key (module clipmenu, novox/hq ADR 0208). Owned by the mesh: replaced at\n# every push. clipmenu shows the history through `dmenu`, the node's dmenu-compatible command, which\n# the holder of node-launcher answers (rofi on the workstations); the chosen entry is put back on the\n# clipboard.\nbindsym $mod+period exec --no-startup-id clipmenu -p Clipboard\n"
+    }
+  ]
+}