fix(ecstore): remove reachable panics in tiering, replication, and heal paths (#4205)

* fix(ecstore): remove reachable panics in tiering, replication, and heal paths

- Parse x-amz-expiration leniently in tier PUT responses; any lifecycle
  rule on the remote tier bucket returns an RFC1123 date that the previous
  ISO8601 unwrap turned into a panic of the ILM transition worker
- Skip invalid user-metadata header values (with a warning) when building
  tier and replication PUT headers instead of panicking on non-ASCII input
- Heal: tolerate absent data_dir for delete markers and remote objects
- transition_object: don't unwrap version_id on unversioned buckets when
  recording partial writes for offline disks
- Admin server info: use port_or_known_default() so default-port (80/443)
  endpoints don't panic is_server_resolvable
- Tier ListObjectsV2 client: decode response body with from_utf8_lossy
- walk_internal: log merge_entry_channels errors instead of dropping them

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(ecstore): fail heal explicitly when data_dir is missing

Address review feedback: unwrap_or_default() silently substituted a nil
UUID when latest metadata lacked data_dir. Delete markers and remote
objects legitimately have no data_dir and skip the data-heal block, but
for a regular object a missing data_dir means corrupt metadata — return
FileCorrupt with a descriptive log instead of building part paths under
a nil UUID directory.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

crates/ecstore/src/diagnostics/admin_server_info.rs

@@ -79,7 +79,9 @@ async fn is_server_resolvable(endpoint: &Endpoint) -> Result<()> {
         "{}://{}:{}",
         endpoint.url.scheme(),
         endpoint.url.host_str().expect("URL should have host"),
-        endpoint.url.port().expect("URL should have port")
+        // `Url::port()` is None when the URL uses the scheme's default port
+        // (e.g. http on 80 / https on 443); fall back to the scheme default.
+        endpoint.url.port_or_known_default().expect("URL should have port")
     );
 
     let ping_task = async {