feat(ui): enhance panel resizing and state persistence

This update introduces functionality for resizing various panels in the UI, including the left sidebar, branch panel, stash panel, and file history. It also adds state persistence for panel sizes and collapsed states using local storage, improving user experience by maintaining preferences across sessions.

- Implemented resizing functionality for multiple UI panels
- Added local storage support for panel dimensions and collapsed states
- Enhanced accessibility features for panel controls

src/lib/components/FileHistoryPanel.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-  import { GitCompare, History, RotateCcw } from "@lucide/svelte";
+  import { ChevronLeft, ChevronRight, GitCompare, History, RotateCcw } from "@lucide/svelte";
   import iconUrl from "../../../src-tauri/icons/icon.png";
   import type { GitCommit } from "../types";
 
@@ -12,6 +12,8 @@
     isLoading?: boolean;
     onDiff: (commit: GitCommit) => void;
     onRestore: (commit: GitCommit) => void;
+    collapsed?: boolean;
+    onToggleCollapsed?: () => void;
   }
 
   let {
@@ -23,6 +25,8 @@
     isLoading = false,
     onDiff = () => {},
     onRestore = () => {},
+    collapsed = false,
+    onToggleCollapsed = () => {},
   }: Props = $props();
 
   function formatCommitDate(value: string): string {
@@ -76,7 +80,23 @@
   }
 </script>
 
-<section class="panel grid grid-rows-[auto_1fr] overflow-hidden" aria-label="Selected file history">
+<section class="panel file-history-panel grid grid-rows-[auto_1fr] overflow-hidden" class:collapsed aria-label="Selected file history">
+  {#if collapsed}
+    <button
+      class="file-history-rail-toggle"
+      type="button"
+      onclick={onToggleCollapsed}
+      aria-expanded={!collapsed}
+      title="Expand file history"
+      aria-label="Expand file history panel"
+    >
+      <ChevronLeft size={16} aria-hidden="true" />
+      <span>File history</span>
+      {#if selectedExplorerPath}
+        <small>{fileHistory.length}</small>
+      {/if}
+    </button>
+  {:else}
   <div class="section-head file-history-head">
     <div class="file-history-heading">
       <span class="eyebrow">{selectedExplorerLabel}</span>
@@ -85,7 +105,19 @@
         use:pathTooltip={selectedExplorerPath}
       >{selectedExplorerPath ? fileName(selectedExplorerPath) : "No file"}</h2>
     </div>
-    <span class="pill pill-count file-history-count">{fileHistory.length}</span>
+    <div class="file-history-head-actions">
+      <span class="pill pill-count file-history-count">{fileHistory.length}</span>
+      <button
+        class="file-history-toggle panel-collapse-toggle"
+        type="button"
+        onclick={onToggleCollapsed}
+        aria-expanded={!collapsed}
+        title="Collapse file history"
+        aria-label="Collapse file history panel"
+      >
+        <ChevronRight size={14} aria-hidden="true" />
+      </button>
+    </div>
   </div>
 
   {#if !hasRepository}
@@ -136,4 +168,5 @@
       {/each}
     </div>
   {/if}
+  {/if}
 </section>