Settings reload: no DNS at build time, don't refuse over old failures

A 3-node rehearsal found every settings reload refused, cluster-wide,
because one node couldn't resolve the Pyzor server:

- PyzorConfig::parse resolved the host while building the settings and
  made a failed lookup a build error. It now keeps the host and port and
  resolves when a message is checked (an IP address is used as is, a
  name is reused for five minutes, the lookup counts against the Pyzor
  timeout). A failure there is a Pyzor error for that message.
- A milter's hostname was resolved the same way, with a blocking
  to_socket_addrs in async code. An IP address is kept; a name is now
  resolved on each connection.

Other build-time I/O is already non-fatal: directories that can't
connect become unavailable with a warning (DIR-21), and the AI model
locality check only warns.

reload_registry swapped the core only when the whole build was free of
errors, while boot runs with whatever built. One failing object thus
refused every later reload, and the running settings went stale. Now a
reload is refused only for errors in objects that built when the
running settings were built (at boot or by the last applied reload):
applying it would lose those. Objects that already failed then are
missing from the running settings anyway, as at boot, so their errors
are logged and returned as known_errors but don't hold the reload back.
Refusing on new errors keeps a bad edit from taking a working object
out of service; the admin gets the error instead.

ReloadSettings now says "Settings were not reloaded." and names the
object and its error ("Tracer with id ...: Only one console tracer is
allowed"), with a count of any further errors. A refused reload after a
directory change logs its errors too.

system::reload::reload_tests (new): with Pyzor enabled on an
unresolvable host, ReloadSettings succeeds (on main it fails with
"Invalid address: failed to lookup address information"); an IP host
needs no lookup; a new build error refuses the reload, names the object
and leaves the running settings unchanged; the same error, once known
from the running settings' build, no longer blocks; once fixed, a new
error there blocks again. smtp::inbound::milter's session test now
names its milter "localhost", so the connect-time lookup is exercised.

crates/jmap/src/registry/mapping/action.rs

@@ -2,6 +2,8 @@
  * SPDX-FileCopyrightText: 2020 Stalwart Labs LLC <[email protected]>
  *
  * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
+ *
+ * Modified by Coffey Labs in 2026 for INBUXA.
  */
 
 use crate::registry::mapping::{RegistrySetResponse, map_bootstrap_error};
@@ -99,7 +101,7 @@ pub(crate) async fn action_set(
                 } else {
                     set.response
                         .not_created
-                        .append(id, map_bootstrap_error(result.errors));
+                        .append(id, reload_refused(result.errors));
                 }
             }
             Action::InvalidateCaches => {
@@ -573,3 +575,34 @@ async fn dmarc_troubleshoot(
 
     Some(request)
 }
+
+/// inbuxa: a refused reload names the object that stopped it and says the
+/// settings weren't applied; upstream passed on the first error's bare message
+/// ("Invalid address: ..."), which read like a problem with the request.
+fn reload_refused(errors: Vec<registry::types::error::Error>) -> SetError<Property> {
+    use registry::types::error::Error;
+    let more = errors.len().saturating_sub(1);
+    let mut description = match errors.first() {
+        Some(Error::Build { object_id, message }) => format!("{object_id}: {message}"),
+        Some(Error::Validation { object_id, errors }) => format!(
+            "{object_id}: {}",
+            errors
+                .iter()
+                .map(|err| err.to_string())
+                .collect::<Vec<_>>()
+                .join("; ")
+        ),
+        Some(Error::Internal {
+            object_id: Some(object_id),
+            error,
+        }) => format!("{object_id}: {error}"),
+        Some(Error::Internal { error, .. }) => error.to_string(),
+        Some(Error::NotFound { object_id }) => format!("{object_id} was not found"),
+        None => String::new(),
+    };
+    description.insert_str(0, "Settings were not reloaded. ");
+    if more > 0 {
+        description.push_str(&format!(" ({more} more in the server log.)"));
+    }
+    map_bootstrap_error(errors).with_description(description)
+}

crates/jmap/src/registry/set.rs

@@ -947,10 +947,14 @@ impl RegistrySet for Server {
                     self.cluster_broadcast(common::ipc::BroadcastEvent::RegistryChange(change))
                         .await;
                 }
-                Ok(_) => trc::event!(
-                    Registry(trc::RegistryEvent::BuildWarning),
-                    Details = "Settings didn't reload after a directory change",
-                ),
+                Ok(reload) => {
+                    // inbuxa: name what stopped it
+                    reload.log();
+                    trc::event!(
+                        Registry(trc::RegistryEvent::BuildWarning),
+                        Details = "Settings didn't reload after a directory change",
+                    )
+                }
                 Err(err) => {
                     trc::error!(err.details("Failed to reload directories"));
                 }