✨ feat(vscode): 「改动」tab 重做为整 PR 聚合的主从式内联 diff（git-diff-view）

- 左树右 diff：左栏全 PR 文件树 + 统计条（共改 N · +X−Y · 已查看 M/N），右栏选中单文件内联 diff
- 用 @git-diff-view/react 只渲染当前选中文件，绕开上万行全量渲染的性能坑
- gitea 新增 listPullRequestFiles、getPullRequest 取 merge_base/head，按需回两版原文
- diff 走 merge_base→head 三点口径（与 Gitea 网页一致），getRawFile 404 兜底成全增/全删/改名
- 已查看态按 head sha 落盘、新 push 自然重置；去掉提交列表、原生 diff 与 spx-gitea 虚拟文档 provider

vscode/webview-ui/src/components/BottomTabs.tsx

@@ -10,14 +10,14 @@
 import type { ClaudeProfile } from '../hooks/useIssues'
 import type { ProfilesData } from '../lib/messages'
 import type { Issue, ManagedSessionsData } from '../types'
-import { ClipboardList, GitCommitHorizontal, Layers, MessagesSquare } from 'lucide-react'
+import { ClipboardList, FileDiff, Layers, MessagesSquare } from 'lucide-react'
 import { useState } from 'react'
 import { IssueDetailPanel } from './IssueDetailPanel'
 import { ManagedSessionsPanel } from './ManagedSessionsPanel'
-import { PrCommitsPanel } from './PrCommitsPanel'
+import { PrFilesPanel } from './PrFilesPanel'
 import { ProfileGrid } from './ProfileGrid'
 
-type TabKey = 'issue' | 'profile' | 'sessions' | 'commits'
+type TabKey = 'issue' | 'profile' | 'sessions' | 'changes'
 
 interface BottomTabsProps {
   // Issue tab props (pass-through to IssueDetailPanel)
@@ -87,10 +87,10 @@ export function BottomTabs(props: BottomTabsProps) {
           title="会话"
         />
         <TabButton
-          active={tab === 'commits'}
-          onClick={() => setTab('commits')}
-          icon={<GitCommitHorizontal className="size-4" />}
-          title="提交"
+          active={tab === 'changes'}
+          onClick={() => setTab('changes')}
+          icon={<FileDiff className="size-4" />}
+          title="改动"
         />
       </div>
 
@@ -143,8 +143,8 @@ export function BottomTabs(props: BottomTabsProps) {
             onCloseTab={props.onManagedSessionCloseTab}
           />
         )}
-        {tab === 'commits' && (
-          <PrCommitsPanel issue={props.issue} />
+        {tab === 'changes' && (
+          <PrFilesPanel issue={props.issue} />
         )}
       </div>
     </div>