feat(web): 角色群像按定位配比生成（role_mix 缩减版）

- 契约: CharacterGenerateRequest 加 role_mix{定位:数量}，model_validator 归一
  count=各值之和（每项≥1、总和≤12），缺省退回单一 role+count
- @llm: build_character_gen_context/run_character_gen 加 role_mix 参并注入配比块
  （确定性、无时间戳，守 assemble 纯函数）；router 穿参
- character-gen.md 加"按配比严格分配 role"纪律 + regen prompt_hashes 金标准
- 前端: sanitizeRoleMix/roleMixTotal + buildCharacterGenerateRequest 第4参 +
  useCharacterGen 穿参 + RoleMixEditor + CharacterGenerator 单一/配比双模

apps/web/lib/generation/cards.test.ts

@@ -16,6 +16,8 @@ import {
   mergeCharacterCards,
   mergeWorldEntities,
   MIN_CHARACTER_COUNT,
+  roleMixTotal,
+  sanitizeRoleMix,
   updateCard,
   worldEntityRules,
 } from "./cards";
@@ -62,6 +64,62 @@ describe("buildCharacterGenerateRequest", () => {
       role: "对手",
     });
   });
+
+  it("uses role_mix (count=sum, no single role) when a mix is supplied", () => {
+    expect(
+      buildCharacterGenerateRequest("群像", 1, "忽略", {
+        主角: 1,
+        对手: 2,
+        配角: 3,
+      }),
+    ).toEqual({
+      brief: "群像",
+      count: 6,
+      role_mix: { 主角: 1, 对手: 2, 配角: 3 },
+    });
+  });
+
+  it("falls back to count/role when role_mix is empty", () => {
+    expect(buildCharacterGenerateRequest("群像", 4, "主角", {})).toEqual({
+      brief: "群像",
+      count: 4,
+      role: "主角",
+    });
+  });
+});
+
+describe("sanitizeRoleMix", () => {
+  it("trims roles, drops blanks, clamps counts to >=1, dedups", () => {
+    expect(
+      sanitizeRoleMix([
+        { role: "  主角  ", count: 2 },
+        { role: "", count: 3 }, // 空定位丢弃
+        { role: "对手", count: 0 }, // clamp 到 1
+        { role: "主角", count: 5 }, // 重复定位丢弃（先到先得）
+      ]),
+    ).toEqual({ 主角: 2, 对手: 1 });
+  });
+
+  it("caps the running total at MAX_CHARACTER_COUNT", () => {
+    const out = sanitizeRoleMix([
+      { role: "主角", count: 10 },
+      { role: "对手", count: 5 }, // 只剩 2 额度
+      { role: "配角", count: 3 }, // 无额度，丢弃
+    ]);
+    expect(out).toEqual({ 主角: 10, 对手: 2 });
+    expect(roleMixTotal(out)).toBe(MAX_CHARACTER_COUNT);
+  });
+
+  it("returns empty object when no valid rows", () => {
+    expect(sanitizeRoleMix([{ role: "  ", count: 3 }])).toEqual({});
+  });
+});
+
+describe("roleMixTotal", () => {
+  it("sums counts", () => {
+    expect(roleMixTotal({ 主角: 1, 对手: 2 })).toBe(3);
+    expect(roleMixTotal({})).toBe(0);
+  });
 });
 
 describe("buildCharacterIngestRequest", () => {