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/http/workflow/story_ops/create.rs

@@ -1,8 +1,10 @@
 //! create_story_file: write new story to CRDT/content store.
 
-
 #[allow(unused_imports)]
-use super::super::{create_section_content, next_item_number, read_story_content, replace_section_content, slugify_name, story_stage, write_story_content};
+use super::super::{
+    create_section_content, next_item_number, read_story_content, replace_section_content,
+    slugify_name, story_stage, write_story_content,
+};
 
 pub fn create_story_file(
     root: &std::path::Path,