fix: rust 1.95.0 clippy lints and matrix-sdk 0.17 API changes

Toolchain bump surfaced new lints (derivable_impls,
unnecessary_unwrap, unnecessary_sort_by, while_let_loop,
collapsible_match, unnecessary_option_map_or_else, cmp_owned)
across bft-json-crdt and huskies-server. All fixed mechanically.

Cargo.toml: dropped the no-longer-existing `rustls-tls` matrix-sdk
feature, then chased through the 0.17 API breakage:
- Relation::Reply is now a tuple variant wrapping Reply, not a
  struct variant with `in_reply_to`
- UserIdentifier::UserIdOrLocalpart removed — use
  UserIdentifier::Matrix(MatrixUserIdentifier::new(..))
- SendMessageLikeEventResult no longer exposes event_id directly;
  it's now on the inner `response` field

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/src/chat/transport/matrix/transport_impl.rs

@@ -48,7 +48,7 @@ impl ChatTransport for MatrixTransport {
             .await
             .map_err(|e| format!("Matrix send error: {e}"))?;
 
-        Ok(resp.event_id.to_string())
+        Ok(resp.response.event_id.to_string())
     }
 
     async fn edit_message(