优化: 变更区完善(文件 Diff 预览 + 分支只读列表)

- 变更文件选中后展开 Diff 红绿预览(原 selectFile 拉了 diffContent 但未渲染)
- 分支切换按钮实现只读列表弹窗(拉取分支列表 + 当前分支标记)
- 分支切换提示走 AI 助手(git_branch 工具)

src/components/project/GitChanges.vue

@@ -10,6 +10,29 @@
       </button>
     </div>
 
+    <!-- 分支列表弹窗(只读查看,切换走 AI 工具) -->
+    <div v-if="showBranchPicker" class="gc-branch-picker">
+      <div class="gc-branch-picker-header">
+        <span>{{ $t('gitChanges.branches') }}</span>
+        <button class="gc-branch-picker-close" @click="closeBranchPicker">✕</button>
+      </div>
+      <div v-if="branchLoading" class="gc-loading"><span class="spinner"></span></div>
+      <div v-else class="gc-branch-list">
+        <div
+          v-for="b in branchList"
+          :key="b.name"
+          class="gc-branch-item"
+          :class="{ current: b.is_current }"
+        >
+          <span class="gc-branch-icon">{{ b.is_current ? '●' : '○' }}</span>
+          <span class="gc-branch-name">{{ b.name }}</span>
+          <span v-if="b.is_current" class="gc-branch-tag">HEAD</span>
+        </div>
+        <div v-if="branchList.length === 0" class="gc-empty">{{ $t('gitChanges.noBranches') }}</div>
+      </div>
+      <div class="gc-branch-picker-hint">{{ $t('gitChanges.branchSwitchHint') }}</div>
+    </div>
+
     <div v-if="loading && !gitStatus" class="gc-skeleton">
       <div class="gc-skeleton-row" v-for="i in 6" :key="i"></div>
     </div>
@@ -49,6 +72,25 @@
             <span class="gc-file-name">{{ filePathLeaf(f.path) }}</span>
           </div>
         </div>
+
+        <!-- 变更文件 diff 预览(选中文件时在列表下方展开) -->
+        <div v-if="selectedFile" class="gc-file-diff">
+          <div class="gc-file-diff-header">
+            <span class="gc-file-diff-path">{{ selectedFile }}</span>
+            <button class="gc-file-diff-close" @click="selectedFile = ''; diffContent = ''">✕</button>
+          </div>
+          <div v-if="diffLoading" class="gc-loading"><span class="spinner"></span></div>
+          <div v-else-if="!diffContent" class="gc-diff-empty">{{ $t('gitChanges.noDiff') }}</div>
+          <div v-else class="gc-diff-content">
+            <div v-for="(ln, idx) in fileDiffLines" :key="idx" class="diff-line" :class="'diff-' + ln.type">
+              <span class="diff-hdr-text" v-if="ln.type === 'hdr'">{{ ln.text }}</span>
+              <template v-else>
+                <span class="diff-line-prefix">{{ ln.prefix }}</span>
+                <span class="diff-line-text">{{ ln.text }}</span>
+              </template>
+            </div>
+          </div>
+        </div>
       </div>
 
       <!-- ====== 提交历史 ====== -->
@@ -200,6 +242,7 @@ interface DiffLine {
 }
 
 const commitDiffLines = computed<DiffLine[]>(() => parseDiff(commitDiff.value))
+const fileDiffLines = computed<DiffLine[]>(() => parseDiff(diffContent.value))
 
 function parseDiff(text: string): DiffLine[] {
   if (!text) return []
@@ -277,8 +320,31 @@ async function loadStatus() {
 }
 
 /** 占位:分支切换后续接入(需拉取分支列表 + checkout IPC)。 */
-function onSwitchBranch() {
-  // TODO: 弹出分支列表选择 + 调用 git checkout
+const showBranchPicker = ref(false)
+const branchList = ref<{ name: string; is_current: boolean }[]>([])
+const branchLoading = ref(false)
+const currentBranch = ref('')
+
+async function onSwitchBranch() {
+  if (showBranchPicker.value) {
+    showBranchPicker.value = false
+    return
+  }
+  showBranchPicker.value = true
+  branchLoading.value = true
+  try {
+    const res = await moduleApi.listBranches(props.moduleId)
+    branchList.value = res.branches
+    currentBranch.value = res.current
+  } catch {
+    branchList.value = []
+  } finally {
+    branchLoading.value = false
+  }
+}
+
+function closeBranchPicker() {
+  showBranchPicker.value = false
 }
 
 async function loadMoreCommits() {
@@ -417,6 +483,27 @@ watch(() => props.moduleId, loadStatus, { immediate: true })
   position: sticky; top: 0; z-index: 1;
 }
 
+/* 变更文件 diff 预览(列表下方展开) */
+.gc-file-diff {
+  margin-top: 8px;
+  border-top: 0.5px solid var(--df-border);
+}
+.gc-file-diff-header {
+  display: flex;
+  align-items: center;
+  padding: 6px 14px;
+  background: rgba(255,255,255,0.03);
+  font-family: var(--df-font-mono, Consolas, monospace);
+  font-size: 11px;
+  border-bottom: 0.5px solid var(--df-border);
+}
+.gc-file-diff-path { flex: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; color: var(--df-text); }
+.gc-file-diff-close {
+  background: none; border: none; color: var(--df-text-dim);
+  cursor: pointer; font-size: 14px; padding: 0 4px;
+}
+.gc-file-diff-close:hover { color: var(--df-text); }
+
 /* Diff 预览 */
 .gc-diff-content {
   font-family: var(--df-font-mono, Consolas, monospace);
@@ -511,6 +598,55 @@ watch(() => props.moduleId, loadStatus, { immediate: true })
 }
 .gc-load-more:hover { background: rgba(255,255,255,0.04); }
 
+/* 分支列表弹窗 */
+.gc-branch-picker {
+  border-bottom: 0.5px solid var(--df-border);
+  background: var(--df-bg);
+}
+.gc-branch-picker-header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: 6px 14px;
+  font-size: 11px;
+  font-weight: 600;
+  color: var(--df-text-dim);
+  text-transform: uppercase;
+}
+.gc-branch-picker-close {
+  background: none; border: none; color: var(--df-text-dim);
+  cursor: pointer; font-size: 14px; padding: 0 4px;
+}
+.gc-branch-list {
+  max-height: 200px;
+  overflow-y: auto;
+  scrollbar-width: thin;
+}
+.gc-branch-item {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  padding: 5px 14px;
+  font-size: 12px;
+  cursor: default;
+}
+.gc-branch-item.current { color: var(--df-accent); }
+.gc-branch-icon { font-size: 10px; flex-shrink: 0; }
+.gc-branch-name { font-family: var(--df-font-mono, Consolas, monospace); }
+.gc-branch-tag {
+  font-size: 9px;
+  padding: 1px 5px;
+  border-radius: 3px;
+  background: rgba(108,99,255,0.15);
+  color: var(--df-accent);
+}
+.gc-branch-picker-hint {
+  padding: 6px 14px;
+  font-size: 11px;
+  color: var(--df-text-dim);
+  border-top: 0.5px solid var(--df-border);
+}
+
 /* 骨架屏 */
 .gc-skeleton {
   padding: 14px;

src/i18n/en/gitChanges.ts

@@ -14,5 +14,8 @@ export default {
     detached: 'HEAD detached',
     loadMore: 'Load more',
     switchBranch: 'Switch branch',
+    branches: 'Branches',
+    noBranches: 'No branches',
+    branchSwitchHint: 'Use AI assistant to switch branches (git_branch tool)',
   },
 }

src/i18n/zh-CN/gitChanges.ts

@@ -14,5 +14,8 @@ export default {
     detached: 'HEAD 分离',
     loadMore: '加载更多',
     switchBranch: '切换分支',
+    branches: '分支列表',
+    noBranches: '无分支',
+    branchSwitchHint: '分支切换请通过 AI 助手执行(git_branch 工具)',
   },
 }