refactor: replace author image URL logic with derived stores

Refactor the author image URL logic in multiple components to use 
derived stores for better reactivity and cleaner code. This change 
eliminates redundant code and ensures that the author image URL 
updates automatically when the user or commit data changes.

Author: GordonBeeming

apps/desktop/src/lib/commit/CommitCard.svelte

@@ -137,10 +137,11 @@
 	}
 
 	const commitShortSha = commit.id.substring(0, 7);
-	const authorImgUrl =
-		commit.author.email?.toLowerCase() === $user?.email?.toLowerCase()
+	const authorImgUrl = $derived.by(() => {
+		return commit.author.email?.toLowerCase() === $user?.email?.toLowerCase()
 			? $user?.picture
 			: commit.author.gravatarUrl;
+	});
 
 	function handleUncommit(e: MouseEvent) {
 		e.stopPropagation();

apps/desktop/src/lib/components/EditMode.svelte

@@ -42,7 +42,14 @@
 
 	let initialFiles = $state<[RemoteFile, ConflictEntryPresence | undefined][]>([]);
 	let commit = $state<Commit | undefined>(undefined);
-	let authorImgUrl = $state<string | undefined>(undefined);
+	const authorImgUrl = $derived.by(() => {
+		if (commit) {
+			return commit.author.email?.toLowerCase() === $user?.email?.toLowerCase()
+				? $user?.picture
+				: commit.author.gravatarUrl;
+		}
+		return undefined;
+	});
 
 	let filesList = $state<HTMLDivElement | undefined>(undefined);
 	let contextMenu = $state<ReturnType<typeof FileContextMenu> | undefined>(undefined);
@@ -59,15 +66,6 @@
 		});
 	});
 
-	$effect(() => {
-		if (commit) {
-			authorImgUrl =
-				commit.author.email?.toLowerCase() === $user?.email?.toLowerCase()
-					? $user?.picture
-					: commit.author.gravatarUrl;
-		}
-	});
-
 	interface FileEntry {
 		name: string;
 		path: string;

apps/desktop/src/lib/navigation/BranchListingSidebarEntry.svelte

@@ -96,7 +96,10 @@
 		if (ownedByUser) {
 			const name = (await gitConfigService.get('user.name')) || unknownName;
 			const email = (await gitConfigService.get('user.email')) || unknownEmail;
-			const srcUrl = $user?.picture ? $user?.picture : await gravatarUrlFromEmail(email);
+			const srcUrl =
+				email.toLowerCase() === $user?.email?.toLowerCase()
+					? $user?.picture
+					: await gravatarUrlFromEmail(email);
 
 			avatars = [{ name, srcUrl }];
 		} else if (branchListingDetails) {

apps/desktop/src/lib/navigation/PullRequestSidebarEntry.svelte

@@ -19,10 +19,11 @@
 	const userService = getContext(UserService);
 	const user = userService.user;
 
-	const authorImgUrl =
-		pullRequest.author?.email?.toLowerCase() === $user?.email?.toLowerCase()
+	const authorImgUrl = $derived.by(() => {
+		return pullRequest.author?.email?.toLowerCase() === $user?.email?.toLowerCase()
 			? $user?.picture
 			: pullRequest.author?.gravatarUrl;
+	});
 
 	function onMouseDown() {
 		goto(formatPullRequestURL(project, pullRequest.number));