feat(ux): R1+R2 审稿裁决人体学 — 冲突卡内联片段 + 分组/排序/跳下一条/主次按钮

R1: 新 lib/review/snippet.ts 从 where 解析段号取终稿命中段预览，ConflictCard 渲染引用块。
R2: 新 lib/review/grouping.ts 按 type 分组+严重度排序（仅改显示顺序，保留原始 index 守 conflict_index 不变量），组计数徽标、跳到下一条未裁决（环回）、采纳改法主按钮/忽略手改次级。
TDD: snippet 8 测 + grouping 10 测。前端门禁绿: lint/tsc/vitest 201/build。

apps/web/lib/review/grouping.test.ts

@@ -0,0 +1,89 @@
+import { describe, expect, it } from "vitest";
+
+import { emptyDecisions, setVerdict } from "./decisions";
+import {
+  displayOrder,
+  groupConflicts,
+  nextUnresolvedInOrder,
+} from "./grouping";
+import type { ReviewConflict } from "./sse";
+
+function conflict(type: string, suggestion = "x"): ReviewConflict {
+  return { type, where: "", refs: [], suggestion };
+}
+
+describe("groupConflicts", () => {
+  it("groups by type and carries the original index", () => {
+    const conflicts = [
+      conflict("性格漂移", "a"),
+      conflict("设定违例", "b"),
+      conflict("性格漂移", "c"),
+    ];
+    const groups = groupConflicts(conflicts);
+    const drift = groups.find((g) => g.type === "性格漂移");
+    expect(drift?.items.map((it) => it.index)).toEqual([0, 2]);
+    expect(drift?.items.map((it) => it.conflict.suggestion)).toEqual(["a", "c"]);
+  });
+
+  it("orders groups by severity (设定违例 before 性格漂移)", () => {
+    const groups = groupConflicts([
+      conflict("性格漂移"),
+      conflict("设定违例"),
+    ]);
+    expect(groups.map((g) => g.type)).toEqual(["设定违例", "性格漂移"]);
+  });
+
+  it("places unknown types after the known five", () => {
+    const groups = groupConflicts([conflict("排版错误"), conflict("能力不符")]);
+    expect(groups.map((g) => g.type)).toEqual(["能力不符", "排版错误"]);
+  });
+
+  it("returns an empty array for no conflicts", () => {
+    expect(groupConflicts([])).toEqual([]);
+  });
+});
+
+describe("displayOrder", () => {
+  it("flattens grouped indices in display order", () => {
+    const groups = groupConflicts([
+      conflict("性格漂移"),
+      conflict("设定违例"),
+      conflict("性格漂移"),
+    ]);
+    // 设定违例(index 1) 先，再 性格漂移(0,2)
+    expect(displayOrder(groups)).toEqual([1, 0, 2]);
+  });
+});
+
+describe("nextUnresolvedInOrder", () => {
+  const order = [1, 0, 2];
+
+  it("finds the first unresolved when nothing is focused", () => {
+    const drafts = emptyDecisions(3);
+    expect(nextUnresolvedInOrder(order, drafts, null)).toBe(1);
+  });
+
+  it("advances to the next unresolved after the focused index", () => {
+    let drafts = emptyDecisions(3);
+    drafts = setVerdict(drafts, 1, "accept");
+    expect(nextUnresolvedInOrder(order, drafts, 1)).toBe(0);
+  });
+
+  it("wraps around to earlier unresolved items", () => {
+    let drafts = emptyDecisions(3);
+    drafts = setVerdict(drafts, 2, "ignore");
+    expect(nextUnresolvedInOrder(order, drafts, 2)).toBe(1);
+  });
+
+  it("returns null when all are resolved", () => {
+    let drafts = emptyDecisions(3);
+    drafts = setVerdict(drafts, 0, "accept");
+    drafts = setVerdict(drafts, 1, "accept");
+    drafts = setVerdict(drafts, 2, "accept");
+    expect(nextUnresolvedInOrder(order, drafts, null)).toBeNull();
+  });
+
+  it("returns null for an empty order", () => {
+    expect(nextUnresolvedInOrder([], [], null)).toBeNull();
+  });
+});