fix: commit minor fmt residue blocking mergemaster cherry-picks

Master had 8 uncommitted single-line whitespace changes (blank-line trimming
in test mod headers, etc.) left over from a previous mergemaster cargo-fmt
run that didn't get committed. Each subsequent merge attempt hit:

  cherry-pick failed: 'Your local changes to the following files would be
  overwritten by merge. Please commit your changes or stash them.'

So merges had been silently un-mergeable for the last several rounds —
mergemaster correctly reported the issue but had no way to fix master's
own state from inside the merge_workspace.

Files affected (all whitespace-only):
- chat/transport/matrix/bot/messages/{handle_message,on_room_message}.rs
- chat/transport/slack/commands/{llm,mod}.rs
- http/mcp/agent_tools/worktree.rs
- http/workflow/story_ops/{create,criterion,update}.rs

cargo clippy --all-targets -- -D warnings: clean
cargo fmt --all --check: clean
2636 tests pass.

server/src/chat/transport/slack/commands/llm.rs

@@ -193,4 +193,3 @@ pub(super) async fn handle_llm_message(
 }
 
 // ── Tests ───────────────────────────────────────────────────────────────
-

server/src/chat/transport/slack/commands/mod.rs

@@ -353,7 +353,6 @@ mod tests {
     use super::*;
     use std::collections::HashMap;
 
-
     #[test]
     fn parse_slash_command_payload() {
         let body = "command=%2Fhuskies-status&text=&user_id=U123&channel_id=C456";