fix(nix): give the launcher a shell and coreutils/gnused on PATH

scripts/start.js shells out to `npm run prisma:migrate`, but the wrapper
only put nodejs and openssl on PATH, so npm could not spawn a shell at
all and every boot logged

  npm error syscall spawn sh
  npm error enoent spawn sh ENOENT

This was never fatal — the systemd unit's ExecStartPre already applies
migrations — but it is pure noise in the journal and it made the real
bcrypt crash harder to spot.

A shell alone is not enough: pnpm's generated node_modules/.bin/prisma
is itself a /bin/sh script that resolves its basedir with `dirname` and
`sed`. Ship bash, coreutils and gnused so the launcher stands on its own
under any caller's environment — the systemd unit's PATH, docker
compose, or a bare shell — rather than depending on what the caller
happens to export.

Verified: with PATH set to /nonexistent, the wrapper now applies all 25
migrations and starts the daemon cleanly.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QBjd9Rw4ct134JH3CnLVaw

package.nix

@@ -9,6 +9,9 @@
   # 7.x in nixpkgs which doesn't ship libquery_engine.node, so we'd fail
   # at postinstall.
   prisma-engines_6,
+  bash,
+  coreutils,
+  gnused,
   openssl,
   sqlite,
   python311,
@@ -131,7 +134,22 @@ stdenv.mkDerivation (finalAttrs: {
     makeWrapper ${lib.getExe nodejs_24} $out/bin/nsecbunkerd \
       --add-flags $out/share/nsecbunkerd/scripts/start.js \
       --set NODE_ENV production \
-      --prefix PATH : ${lib.makeBinPath [ openssl nodejs_24 ]} \
+      --prefix PATH : ${
+        lib.makeBinPath [
+          openssl
+          nodejs_24
+          # scripts/start.js shells out to `npm run prisma:migrate`, and
+          # npm needs a shell to spawn at all. The pnpm-generated
+          # `node_modules/.bin/prisma` shim is itself a /bin/sh script
+          # that resolves its basedir with `dirname` + `sed`. Ship all
+          # three so the launcher works under any caller's environment
+          # (the systemd unit's PATH, docker compose, a bare shell)
+          # rather than depending on what the caller happens to export.
+          bash
+          coreutils
+          gnused
+        ]
+      } \
       ${
         lib.concatStringsSep " \\\n      " (
           lib.mapAttrsToList (n: v: "--set ${n} ${lib.escapeShellArg v}") prismaEnv