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/commands/loc.rs

@@ -135,7 +135,7 @@ fn loc_top_n(project_root: &std::path::Path, top_n: usize) -> String {
         })
         .collect();
 
-    files.sort_by(|a, b| b.0.cmp(&a.0));
+    files.sort_by_key(|b| std::cmp::Reverse(b.0));
     files.truncate(top_n);
 
     if files.is_empty() {