Optimize repository loading and enhance Git UI

Consolidate multiple Git backend calls into a single bundle to reduce
overhead when opening and auto-refreshing repositories. This significantly
improves performance by fetching status, branches, commits, and files
in one optimized operation, instead of re-running 'git rev-parse' and
'git status' multiple times.

Also, streamline commit history loading by fetching file changes inline
via 'git log --name-status -z', eliminating expensive per-commit
'git diff-tree' processes.

Additionally, introduce the ability to create new branches from a
specific commit in the history and refactor the commit comparison
feature into a dedicated dialog. The status panel now displays concise
file names.

src/lib/git.ts

@@ -8,6 +8,7 @@ import type {
   GitRepositoryFile,
   GitSearchHit,
   GitStatus,
+  RepositoryBundle,
   StoredCredential,
 } from "./types";
 
@@ -15,6 +16,10 @@ export function openRepository(path: string): Promise<GitStatus> {
   return invoke<GitStatus>("open_repository", { path });
 }
 
+export function openRepositoryBundle(path: string, commitLimit = 100): Promise<RepositoryBundle> {
+  return invoke<RepositoryBundle>("open_repository_bundle", { path, commitLimit });
+}
+
 export function getStatus(path: string): Promise<GitStatus> {
   return invoke<GitStatus>("get_status", { path });
 }
@@ -27,8 +32,12 @@ export function checkoutBranch(path: string, branch: string): Promise<GitStatus>
   return invoke<GitStatus>("checkout_branch", { path, branch });
 }
 
-export function createBranch(path: string, branch: string): Promise<GitStatus> {
-  return invoke<GitStatus>("create_branch", { path, branch });
+export function createBranch(
+  path: string,
+  branch: string,
+  startPoint?: string,
+): Promise<GitStatus> {
+  return invoke<GitStatus>("create_branch", { path, branch, startPoint: startPoint ?? null });
 }
 
 export function stageFiles(path: string, files: string[]): Promise<GitStatus> {