feat(git): Add comprehensive worktree management capabilities

This update introduces full support for Git worktrees, allowing users to manage multiple isolated working copies within a single repository. This includes new functionality to list, add, remove, move, lock, and repair worktrees, significantly enhancing the repository's capability to handle parallel development streams.

- Added `GitWorktree` structure definition across API contracts and Rust backend
- Implemented full CRUD operations for worktrees in Tauri commands
- Updated UI components (App.svelte, BranchPanel.svelte) to expose worktree management dialog

src/lib/types.ts

@@ -90,6 +90,24 @@ export interface GitBranch {
   remote: boolean;
 }
 
+export interface GitWorktree {
+  path: string;
+  head: string | null;
+  short_head: string | null;
+  branch: string | null;
+  bare: boolean;
+  detached: boolean;
+  locked: boolean;
+  lock_reason: string | null;
+  prunable: boolean;
+  prune_reason: string | null;
+  missing: boolean;
+  is_main: boolean;
+  is_current: boolean;
+  clean: boolean;
+  changed_files: number;
+}
+
 export interface GitTag {
   name: string;
   hash: string;