fix(stack-service): normalize commit stats shape (#12370)

Convert various backend commit stats shapes into a single frontend
format expected by the UI. Some responses use camelCase keys
(linesAdded/linesRemoved/filesChanged) while others use snake_case
(lines_added/lines_removed/files_changed). The code now detects the
shape and maps snake_case to the canonical camelCase shape before
storing in the response transform.

This prevents mismatched stat access and makes downstream code rely on
one consistent stats object.

Author: PavelLaptev

apps/desktop/src/lib/stacks/stackService.svelte.ts

@@ -1175,10 +1175,11 @@ function injectEndpoints(api: ClientState['backendApi'], uiState: UiState) {
 				],
 				transformResponse(rsp: CommitDetails) {
 					const changes = changesAdapter.addMany(changesAdapter.getInitialState(), rsp.changes);
+					const stats = rsp.stats;
 					return {
 						changes: changes,
 						details: rsp.commit,
-						stats: rsp.stats,
+						stats,
 						conflictEntries: rsp.conflictEntries
 							? new ConflictEntries(
 									rsp.conflictEntries.ancestorEntries,

crates/but-core/src/diff/commit_details.rs

@@ -13,6 +13,7 @@ pub struct CommitDetails {
 
 /// Line statistics obtained from diffing the blobs of one or more [TreeChange](crate::TreeChange).
 #[derive(Default, Debug, Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Hash, serde::Serialize)]
+#[serde(rename_all = "camelCase")]
 pub struct LineStats {
     /// The total amount of lines added in the between blobs of the two trees.
     pub lines_added: u64,