fix(admin): city-scoped district pick and clearer overlap errors

Region partners only select districts under the chosen city; overlap errors name the occupying partner.

Co-authored-by: Cursor <cursoragent@cursor.com>

packages/domain/src/city-partner.test.ts

@@ -63,10 +63,21 @@ describe('validatePartnerCityBinding', () => {
 
   it('rejects overlapping district codes', () => {
     const result = validatePartnerCityBinding(
-      [{ id: '1', partnerAccountId: '10', scopeType: 'DISTRICT', districtCodes: ['410105'] }],
+      [
+        {
+          id: '1',
+          partnerAccountId: '10',
+          scopeType: 'DISTRICT',
+          districtCodes: ['410105'],
+          companyName: '甲公司',
+        },
+      ],
       { partnerAccountId: '11', scopeType: 'DISTRICT', districtCodes: ['410105'] },
     );
     expect(result.ok).toBe(false);
+    expect(result.message).toContain('区域重合');
+    expect(result.message).toContain('甲公司');
+    expect(result.occupiedCodes).toEqual(['410105']);
   });
 
   it('allows valid district binding', () => {

packages/domain/src/city-partner.ts

@@ -7,6 +7,8 @@ export interface PartnerCityBindingInput {
   scopeType: CityPartnerScopeType;
   districtCodes?: string[] | null;
   bindingStatus?: CityPartnerStatus;
+  /** 仅用于重合报错文案 */
+  companyName?: string | null;
 }
 
 export interface PartnerCityResolveRef {
@@ -20,6 +22,7 @@ export interface PartnerCityResolveRef {
 export interface PartnerCityValidationResult {
   ok: boolean;
   message?: string;
+  occupiedCodes?: string[];
 }
 
 function normalizeDistrictCodes(codes?: string[] | null): string[] {
@@ -98,18 +101,25 @@ export function validatePartnerCityBinding(
     return { ok: false, message: '区域合伙人须至少选择一个区县' };
   }
 
-  const occupied = new Set<string>();
+  const occupiedBy = new Map<string, string>();
   for (const row of others) {
     if (row.scopeType !== 'DISTRICT') continue;
+    const owner = row.companyName?.trim() || '其他区域合伙人';
     for (const code of normalizeDistrictCodes(row.districtCodes)) {
-      occupied.add(code);
+      if (!occupiedBy.has(code)) occupiedBy.set(code, owner);
     }
   }
 
-  for (const code of districts) {
-    if (occupied.has(code)) {
-      return { ok: false, message: `区县 ${code} 已被其他区域合伙人占用` };
-    }
+  const overlaps = districts.filter((code) => occupiedBy.has(code));
+  if (overlaps.length) {
+    const detail = overlaps
+      .map((code) => `${code}（${occupiedBy.get(code)}）`)
+      .join('、');
+    return {
+      ok: false,
+      message: `区域重合：以下区县已被占用，请改选其他区县 — ${detail}`,
+      occupiedCodes: overlaps,
+    };
   }
 
   return { ok: true };