feat(vscode-ide-companion): 改进消息排序和显示逻辑

- 添加时间戳支持，确保消息按时间顺序排列
- 更新工具调用处理逻辑，自动添加和保留时间戳
- 修改消息渲染逻辑，将所有类型的消息合并排序后统一渲染
- 优化完成的工具调用显示，修复显示顺序问题
- 调整进行中的工具调用显示，统一到消息流中展示
- 移除重复的计划展示逻辑，避免最新块重复出现
- 重构消息处理和渲染代码，提高可维护性

packages/vscode-ide-companion/src/webview/utils/simpleDiff.ts

@@ -0,0 +1,92 @@
+/**
+ * @license
+ * Copyright 2025 Qwen Team
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Minimal line-diff utility for webview previews.
+ *
+ * This is a lightweight LCS-based algorithm to compute add/remove operations
+ * between two texts. It intentionally avoids heavy dependencies and is
+ * sufficient for rendering a compact preview inside the chat.
+ */
+
+export type DiffOp =
+  | { type: 'add'; line: string; newIndex: number }
+  | { type: 'remove'; line: string; oldIndex: number };
+
+/**
+ * Compute a minimal line-diff (added/removed only).
+ * - Equal lines are omitted from output by design (we only preview changes).
+ * - Order of operations follows the new text progression so the preview feels natural.
+ */
+export function computeLineDiff(
+  oldText: string | null | undefined,
+  newText: string | undefined,
+): DiffOp[] {
+  const a = (oldText || '').split('\n');
+  const b = (newText || '').split('\n');
+
+  const n = a.length;
+  const m = b.length;
+
+  // Build LCS DP table
+  const dp: number[][] = Array.from({ length: n + 1 }, () =>
+    new Array(m + 1).fill(0),
+  );
+  for (let i = n - 1; i >= 0; i--) {
+    for (let j = m - 1; j >= 0; j--) {
+      if (a[i] === b[j]) {
+        dp[i][j] = dp[i + 1][j + 1] + 1;
+      } else {
+        dp[i][j] = Math.max(dp[i + 1][j], dp[i][j + 1]);
+      }
+    }
+  }
+
+  // Walk to produce operations
+  const ops: DiffOp[] = [];
+  let i = 0;
+  let j = 0;
+  while (i < n && j < m) {
+    if (a[i] === b[j]) {
+      i++;
+      j++;
+    } else if (dp[i + 1][j] >= dp[i][j + 1]) {
+      // remove a[i]
+      ops.push({ type: 'remove', line: a[i], oldIndex: i });
+      i++;
+    } else {
+      // add b[j]
+      ops.push({ type: 'add', line: b[j], newIndex: j });
+      j++;
+    }
+  }
+
+  // Remaining tails
+  while (i < n) {
+    ops.push({ type: 'remove', line: a[i], oldIndex: i });
+    i++;
+  }
+  while (j < m) {
+    ops.push({ type: 'add', line: b[j], newIndex: j });
+    j++;
+  }
+
+  return ops;
+}
+
+/**
+ * Truncate a long list of operations for preview purposes.
+ * Keeps first `head` and last `tail` operations, inserting a gap marker.
+ */
+export function truncateOps<T>(
+  ops: T[],
+  head = 120,
+  tail = 80,
+): { items: T[]; truncated: boolean; omitted: number } {
+  if (ops.length <= head + tail) {
+    return { items: ops, truncated: false, omitted: 0 };
+  }
+  const items = [...ops.slice(0, head), ...ops.slice(-tail)];
+  return { items, truncated: true, omitted: ops.length - head - tail };
+}