feat(hetzner): give stalwart read access to certain keys

servers/hetzner/modules/services/stalwart.nix

@@ -262,7 +262,12 @@ in {
 
   systemd.services.stalwart-cert-perm = {
     description = "Grant stalwart read access to its TLS private key";
-    after = ["tlsa-update.service" "stalwart.service"];
+    # Belt-and-suspenders: tlsa-update already chgrps the key after every sync;
+    # this guarantees the group grant also exists at first boot, before stalwart
+    # starts (previously ordered after stalwart, so a fresh sync could leave a
+    # root:root key and webadmin reload would fail with EACCES).
+    after = ["tlsa-update.service"];
+    before = ["stalwart.service"];
     partOf = ["tlsa-update.service"];
     wantedBy = ["multi-user.target"];
     path = [pkgs.coreutils];

servers/hetzner/modules/services/tlsa-updater.nix

@@ -33,6 +33,10 @@
     #    users.
     install -D -m 0644 "$SRC_CERT" "$DST_CERT"
     install -D -m 0640 "$SRC_KEY"  "$DST_KEY"
+    # Stalwart reads the key as user "stalwart" via %{file:...}%; regrant the
+    # group immediately so every sync leaves it readable (0640 root:stalwart)
+    # and webadmin config reload never fails with EACCES.
+    chgrp stalwart "$DST_KEY"
 
     # 2) TLSA 3 1 1 = SHA-256 of the certificate's SubjectPublicKeyInfo (SPKI),
     #    NOT the whole certificate. Matching type 1 = SHA-256 of the SPKI DER.