diff --git a/src/app.module.ts b/src/app.module.ts
index 46728a0..36ee2ce 100644
--- a/src/app.module.ts
+++ b/src/app.module.ts
@@ -29,6 +29,7 @@ import { AgencyModule } from './agency/agency.module.js';
 import { StaffModule } from './staff/staff.module.js';
 import { CatalogModule } from './catalog/catalog.module.js';
 import { StorageModule } from './storage/storage.module.js';
+import { ElderModule } from './elder/elder.module.js';
 import { AppController } from './app.controller.js';
 import { AppService } from './app.service.js';
 
@@ -55,6 +56,7 @@ import { AppService } from './app.service.js';
     StaffModule,
     CatalogModule,
     StorageModule,
+    ElderModule,
   ],
   controllers: [AppController],
   providers: [
diff --git a/src/elder/dto.ts b/src/elder/dto.ts
new file mode 100644
index 0000000..ad6fbcf
--- /dev/null
+++ b/src/elder/dto.ts
@@ -0,0 +1,164 @@
+import { ApiProperty, ApiPropertyOptional } from '@nestjs/swagger';
+import { IsDateString, IsIn, IsInt, IsNotEmpty, IsOptional, IsString, MaxLength } from 'class-validator';
+import { PageQuery } from '../common/page.dto.js';
+
+/**
+ * 老人档案（elder）DTO。字段字典以 shared/data-model 为准（ltc_elder）。
+ * - 不含 tenantCode/createdBy/createdAt/updatedAt/deletedAt（系统字段，服务端注入）；
+ * - birth_date 由身份证 7-14 位带出，不接受前端传入；
+ * - treat_status/status_source 由服务端定，不接受前端传入；
+ * - id_card_no 本期存明文（加密机制由后续安全 change 统一落地，见 elder.service.ts TODO）。
+ */
+export class CreateElderDto {
+  @ApiProperty({ description: '参保地/统筹区 code（loc_code）' })
+  @IsString()
+  @IsNotEmpty()
+  locCode!: string;
+
+  @ApiProperty({ description: '姓名' })
+  @IsString()
+  @IsNotEmpty()
+  @MaxLength(30)
+  name!: string;
+
+  @ApiProperty({ description: '性别：M/F' })
+  @IsString()
+  @IsNotEmpty()
+  @IsIn(['M', 'F'])
+  gender!: string;
+
+  @ApiProperty({ description: '身份证号（18 位，服务端做 GB11643 校验位校验）' })
+  @IsString()
+  @IsNotEmpty()
+  idCardNo!: string;
+
+  @ApiPropertyOptional({ description: '联系电话' })
+  @IsOptional()
+  @IsString()
+  phone?: string;
+
+  @ApiProperty({ description: '居住地址' })
+  @IsString()
+  @IsNotEmpty()
+  @MaxLength(200)
+  address!: string;
+
+  @ApiPropertyOptional({ description: '紧急联系人' })
+  @IsOptional()
+  @IsString()
+  guardianName?: string;
+
+  @ApiPropertyOptional({ description: '紧急联系人电话' })
+  @IsOptional()
+  @IsString()
+  guardianPhone?: string;
+
+  @ApiProperty({ description: '医保参保号' })
+  @IsString()
+  @IsNotEmpty()
+  insurNo!: string;
+
+  @ApiProperty({ description: '参保类型：employee/resident' })
+  @IsString()
+  @IsNotEmpty()
+  insurType!: string;
+
+  @ApiPropertyOptional({ description: '缴费年限' })
+  @IsOptional()
+  @IsInt()
+  insurYears?: number;
+
+  @ApiPropertyOptional({ description: '参保核验状态：verified/unverified' })
+  @IsOptional()
+  @IsString()
+  insurVerifyStatus?: string;
+
+  @ApiPropertyOptional({ description: '参保核验日期（YYYY-MM-DD）' })
+  @IsOptional()
+  @IsDateString()
+  insurVerifyDate?: string;
+
+  @ApiPropertyOptional({ description: '失能等级（sev_1/sev_2/sev_3），有值则须上传评估结论副本' })
+  @IsOptional()
+  @IsString()
+  assessLevel?: string;
+
+  @ApiPropertyOptional({ description: '护理等级（care_1/care_2/care_3），有值则须上传评估结论副本' })
+  @IsOptional()
+  @IsString()
+  careLevel?: string;
+
+  @ApiPropertyOptional({ description: '评估结论日期（YYYY-MM-DD）' })
+  @IsOptional()
+  @IsDateString()
+  assessDate?: string;
+
+  @ApiPropertyOptional({ description: '评估机构名称' })
+  @IsOptional()
+  @IsString()
+  assessOrg?: string;
+
+  @ApiPropertyOptional({ description: '评估结论副本 MinIO key（有等级则必填）' })
+  @IsOptional()
+  @IsString()
+  assessEvidenceFile?: string;
+
+  @ApiPropertyOptional({ description: '待遇有效期起（YYYY-MM-DD）' })
+  @IsOptional()
+  @IsDateString()
+  benefitStart?: string;
+
+  @ApiPropertyOptional({ description: '待遇有效期止（YYYY-MM-DD）' })
+  @IsOptional()
+  @IsDateString()
+  benefitEnd?: string;
+
+  @ApiPropertyOptional({ description: '住院起（YYYY-MM-DD）' })
+  @IsOptional()
+  @IsDateString()
+  hospStart?: string;
+
+  @ApiPropertyOptional({ description: '住院止（YYYY-MM-DD）' })
+  @IsOptional()
+  @IsDateString()
+  hospEnd?: string;
+
+  @ApiPropertyOptional({ description: '备注' })
+  @IsOptional()
+  @IsString()
+  note?: string;
+}
+
+export class ListElderQuery extends PageQuery {
+  @ApiPropertyOptional({ description: '姓名（模糊）' })
+  @IsOptional()
+  @IsString()
+  name?: string;
+
+  @ApiPropertyOptional({ description: '待遇状态' })
+  @IsOptional()
+  @IsString()
+  treatStatus?: string;
+
+  @ApiPropertyOptional({ description: '失能/护理等级（匹配 assess_level 或 care_level）' })
+  @IsOptional()
+  @IsString()
+  level?: string;
+}
+
+export class ChangeStatusDto {
+  @ApiProperty({ description: '目标待遇状态（十态之一）' })
+  @IsString()
+  @IsNotEmpty()
+  toStatus!: string;
+
+  @ApiProperty({ description: '变更原因（必填）' })
+  @IsString()
+  @IsNotEmpty()
+  changeReason!: string;
+
+  @ApiPropertyOptional({ description: '佐证材料 MinIO key' })
+  @IsOptional()
+  @IsString()
+  evidenceFile?: string;
+}
diff --git a/src/elder/elder.controller.ts b/src/elder/elder.controller.ts
new file mode 100644
index 0000000..5ac4854
--- /dev/null
+++ b/src/elder/elder.controller.ts
@@ -0,0 +1,51 @@
+import { Body, Controller, Get, Param, Post, Query, UploadedFile, UseInterceptors } from '@nestjs/common';
+import { FileInterceptor } from '@nestjs/platform-express';
+import { Permissions } from '../common/permissions.js';
+import { AuditLog, RequirePermissions } from '../auth/decorators.js';
+import { ChangeStatusDto, CreateElderDto, ListElderQuery } from './dto.js';
+import { ElderService } from './elder.service.js';
+
+@Controller('elder')
+export class ElderController {
+  constructor(private readonly service: ElderService) {}
+
+  @Get()
+  @RequirePermissions(Permissions.elder.list)
+  list(@Query() q: ListElderQuery) {
+    return this.service.listElder(q);
+  }
+
+  @Post()
+  @RequirePermissions(Permissions.elder.create)
+  @AuditLog('elder', 'create')
+  create(@Body() dto: CreateElderDto) {
+    return this.service.createElder(dto);
+  }
+
+  @Get(':id')
+  @RequirePermissions(Permissions.elder.detail)
+  detail(@Param('id') id: string) {
+    return this.service.detail(id);
+  }
+
+  @Post(':id/status')
+  @RequirePermissions(Permissions.elder.statusChange)
+  @AuditLog('elder', 'status-change')
+  changeStatus(@Param('id') id: string, @Body() dto: ChangeStatusDto) {
+    return this.service.changeStatus(id, dto);
+  }
+
+  @Get(':id/status/log')
+  @RequirePermissions(Permissions.elder.detail)
+  statusLog(@Param('id') id: string) {
+    return this.service.statusLog(id);
+  }
+
+  @Post('assess-evidence')
+  @RequirePermissions(Permissions.elder.create)
+  @AuditLog('elder', 'upload-evidence')
+  @UseInterceptors(FileInterceptor('file'))
+  uploadEvidence(@UploadedFile() file: { buffer: Buffer; originalname: string }) {
+    return this.service.uploadEvidence(file);
+  }
+}
diff --git a/src/elder/elder.module.ts b/src/elder/elder.module.ts
new file mode 100644
index 0000000..958c08d
--- /dev/null
+++ b/src/elder/elder.module.ts
@@ -0,0 +1,12 @@
+import { Module } from '@nestjs/common';
+import { ElderController } from './elder.controller.js';
+import { ElderService } from './elder.service.js';
+import { StorageModule } from '../storage/storage.module.js';
+import { AuditLogsModule } from '../audit-logs/audit-logs.module.js';
+
+@Module({
+  imports: [StorageModule, AuditLogsModule],
+  controllers: [ElderController],
+  providers: [ElderService],
+})
+export class ElderModule {}
diff --git a/src/elder/elder.service.spec.ts b/src/elder/elder.service.spec.ts
new file mode 100644
index 0000000..fd5a574
--- /dev/null
+++ b/src/elder/elder.service.spec.ts
@@ -0,0 +1,236 @@
+import { describe, expect, it, vi } from 'vitest';
+import { ElderService, maskIdCard } from './elder.service.js';
+import type { PrismaService } from '../prisma/prisma.service.js';
+import type { StorageService } from '../storage/storage.service.js';
+import type { AuditLogsService } from '../audit-logs/audit-logs.service.js';
+import { ErrorCodes } from '../common/error-codes.js';
+import { runWithRequestContext } from '../common/context/request-context.js';
+import type { RequestContext } from '../common/context/request-context.js';
+
+const ctx: RequestContext = {
+  tenantCode: 'T001',
+  userId: 'u1',
+  username: 'admin',
+  super: false,
+  dataScope: 'all',
+  orgCode: null,
+  orgCodes: [],
+};
+
+/** 通过 GB11643 校验位校验的合法身份证（出生日期 1990-01-01）。 */
+const VALID_ID_CARD = '530102199001011231';
+
+const baseDto = {
+  locCode: '530100',
+  name: '张三',
+  gender: 'M',
+  idCardNo: VALID_ID_CARD,
+  phone: '13800000000',
+  address: '昆明市五华区',
+  insurNo: 'INS001',
+  insurType: 'employee',
+};
+
+function makeService(
+  overrides: {
+    elderFindFirst?: ReturnType<typeof vi.fn>;
+    elderFindUnique?: ReturnType<typeof vi.fn>;
+    elderFindMany?: ReturnType<typeof vi.fn>;
+    elderCount?: ReturnType<typeof vi.fn>;
+    elderCreate?: ReturnType<typeof vi.fn>;
+    elderUpdate?: ReturnType<typeof vi.fn>;
+    userRoleFindMany?: ReturnType<typeof vi.fn>;
+    statusLogCreate?: ReturnType<typeof vi.fn>;
+    auditRecord?: ReturnType<typeof vi.fn>;
+  } = {},
+) {
+  const elderFindFirst = overrides.elderFindFirst ?? vi.fn().mockResolvedValue(null);
+  const elderFindUnique = overrides.elderFindUnique ?? vi.fn().mockResolvedValue(null);
+  const elderFindMany = overrides.elderFindMany ?? vi.fn().mockResolvedValue([]);
+  const elderCount = overrides.elderCount ?? vi.fn().mockResolvedValue(0);
+  const elderCreate = overrides.elderCreate ?? vi.fn().mockResolvedValue({ id: 'e1', ...baseDto });
+  const elderUpdate = overrides.elderUpdate ?? vi.fn().mockResolvedValue({ id: 'e1' });
+  const userRoleFindMany = overrides.userRoleFindMany ?? vi.fn().mockResolvedValue([]);
+  const statusLogCreate = overrides.statusLogCreate ?? vi.fn().mockResolvedValue({ id: 'sl1' });
+  const auditRecord = overrides.auditRecord ?? vi.fn().mockResolvedValue(undefined);
+
+  const prisma = {
+    client: {
+      elder: {
+        findFirst: elderFindFirst,
+        findUnique: elderFindUnique,
+        findMany: elderFindMany,
+        count: elderCount,
+        create: elderCreate,
+        update: elderUpdate,
+      },
+      elderStatusLog: { create: statusLogCreate, findMany: vi.fn().mockResolvedValue([]) },
+      userRole: { findMany: userRoleFindMany },
+    },
+  };
+  const storage = {
+    buildKey: vi.fn().mockReturnValue('elder/T001/1-a.jpg'),
+    upload: vi.fn().mockResolvedValue('elder/T001/1-a.jpg'),
+  };
+  const auditLogs = { record: auditRecord };
+  const service = new ElderService(
+    prisma as unknown as PrismaService,
+    storage as unknown as StorageService,
+    auditLogs as unknown as AuditLogsService,
+  );
+  return {
+    service,
+    elderFindFirst,
+    elderFindUnique,
+    elderFindMany,
+    elderCount,
+    elderCreate,
+    elderUpdate,
+    userRoleFindMany,
+    statusLogCreate,
+    auditRecord,
+    storage,
+  };
+}
+
+describe('maskIdCard', () => {
+  it('18 位 → 前4 + 10个* + 后4', () => {
+    expect(maskIdCard('530102199001011231')).toBe('5301**********1231');
+  });
+  it('15 位 → 前3 + 8个* + 后4', () => {
+    expect(maskIdCard('530102900101123')).toBe('530********1123');
+  });
+  it('空串与非常见长度原样返回', () => {
+    expect(maskIdCard('')).toBe('');
+    expect(maskIdCard('123')).toBe('123');
+  });
+});
+
+describe('ElderService', () => {
+  it('create 有等级无评估结论副本 → 抛 ELDER_LEVEL_REQUIRES_EVIDENCE', async () => {
+    const { service, elderCreate } = makeService();
+
+    await expect(
+      runWithRequestContext(ctx, () => service.createElder({ ...baseDto, assessLevel: 'sev_1' })),
+    ).rejects.toMatchObject({ response: { code: ErrorCodes.ELDER_LEVEL_REQUIRES_EVIDENCE } });
+
+    expect(elderCreate).not.toHaveBeenCalled();
+  });
+
+  it('create benefit_start 未来 → treatStatus = waiting_period', async () => {
+    const { service, elderCreate } = makeService();
+
+    await runWithRequestContext(ctx, () =>
+      service.createElder({ ...baseDto, benefitStart: '2099-01-01', benefitEnd: '2099-12-31' }),
+    );
+
+    expect(elderCreate).toHaveBeenCalledWith({
+      data: expect.objectContaining({ treatStatus: 'waiting_period', statusSource: 'manual' }),
+    });
+  });
+
+  it('create 待遇有效期覆盖今天 → treatStatus = active，且出生日期由身份证带出', async () => {
+    const { service, elderCreate } = makeService();
+
+    await runWithRequestContext(ctx, () =>
+      service.createElder({ ...baseDto, benefitStart: '2000-01-01', benefitEnd: '2099-12-31' }),
+    );
+
+    expect(elderCreate).toHaveBeenCalledWith({
+      data: expect.objectContaining({ treatStatus: 'active', birthDate: '1990-01-01' }),
+    });
+  });
+
+  it('同机构重复 id_card_no → 抛 ELDER_ID_CARD_EXISTS', async () => {
+    const elderFindFirst = vi.fn().mockResolvedValue({ id: 'e-other', idCardNo: VALID_ID_CARD });
+    const elderCreate = vi.fn();
+    const { service } = makeService({ elderFindFirst, elderCreate });
+
+    await expect(
+      runWithRequestContext(ctx, () => service.createElder(baseDto)),
+    ).rejects.toMatchObject({ response: { code: ErrorCodes.ELDER_ID_CARD_EXISTS } });
+
+    expect(elderFindFirst).toHaveBeenCalledWith({ where: { idCardNo: VALID_ID_CARD } });
+    expect(elderCreate).not.toHaveBeenCalled();
+  });
+
+  it('changeStatus 缺 changeReason → 抛 ELDER_STATUS_REASON_REQUIRED', async () => {
+    const { service, elderUpdate } = makeService();
+
+    await expect(
+      runWithRequestContext(ctx, () => service.changeStatus('e1', { toStatus: 'active', changeReason: '' })),
+    ).rejects.toMatchObject({ response: { code: ErrorCodes.ELDER_STATUS_REASON_REQUIRED } });
+
+    expect(elderUpdate).not.toHaveBeenCalled();
+  });
+
+  it('changeStatus 写状态日志（from/to/reason/operator）', async () => {
+    const elderFindUnique = vi.fn().mockResolvedValue({ id: 'e1', treatStatus: 'waiting_period', name: '张三' });
+    const { service, statusLogCreate } = makeService({ elderFindUnique });
+
+    const result = await runWithRequestContext(ctx, () =>
+      service.changeStatus('e1', { toStatus: 'active', changeReason: '待遇生效' }),
+    );
+
+    expect(result).toEqual({ id: 'e1', fromStatus: 'waiting_period', toStatus: 'active' });
+    expect(statusLogCreate).toHaveBeenCalledWith({
+      data: expect.objectContaining({
+        elderId: 'e1',
+        tenantCode: 'T001',
+        fromStatus: 'waiting_period',
+        toStatus: 'active',
+        changeReason: '待遇生效',
+        operatorId: 'u1',
+      }),
+    });
+  });
+
+  it('list 返回掩码 id_card_no', async () => {
+    const elderFindMany = vi.fn().mockResolvedValue([
+      { id: 'e1', idCardNo: VALID_ID_CARD, name: '张三', treatStatus: 'active' },
+    ]);
+    const elderCount = vi.fn().mockResolvedValue(1);
+    const { service } = makeService({ elderFindMany, elderCount });
+
+    const res = await runWithRequestContext(ctx, () => service.listElder({ page: 1, pageSize: 20 }));
+
+    expect(res.list[0].idCardNo).toBe('5301**********1231');
+    expect(res.total).toBe(1);
+  });
+
+  it('detail 非 admin/qc 不返回明文', async () => {
+    const elderFindUnique = vi.fn().mockResolvedValue({ id: 'e1', idCardNo: VALID_ID_CARD, name: '张三' });
+    const userRoleFindMany = vi.fn().mockResolvedValue([{ roleCode: 'nurse' }]);
+    const { service, auditRecord } = makeService({ elderFindUnique, userRoleFindMany });
+
+    const res = await runWithRequestContext(ctx, () => service.detail('e1'));
+
+    expect(res.idCardNo).toBe('5301**********1231');
+    expect(auditRecord).not.toHaveBeenCalled();
+  });
+
+  it('detail admin/qc 返回明文并写审计', async () => {
+    const elderFindUnique = vi.fn().mockResolvedValue({ id: 'e1', idCardNo: VALID_ID_CARD, name: '张三' });
+    const userRoleFindMany = vi.fn().mockResolvedValue([{ roleCode: 'admin' }]);
+    const { service, auditRecord } = makeService({ elderFindUnique, userRoleFindMany });
+
+    const res = await runWithRequestContext(ctx, () => service.detail('e1'));
+
+    expect(res.idCardNo).toBe(VALID_ID_CARD);
+    expect(auditRecord).toHaveBeenCalledWith(
+      expect.objectContaining({ module: 'elder', action: 'view-id-card', userId: 'u1' }),
+    );
+  });
+
+  it('uploadEvidence 读 buffer → buildKey + upload → 返回 { key }', async () => {
+    const { service, storage } = makeService();
+
+    const res = await runWithRequestContext(ctx, () =>
+      service.uploadEvidence({ buffer: Buffer.from('x'), originalname: 'a.jpg' }),
+    );
+
+    expect(storage.buildKey).toHaveBeenCalledWith('T001', 'a.jpg');
+    expect(storage.upload).toHaveBeenCalledWith(expect.any(Buffer), 'elder/T001/1-a.jpg');
+    expect(res).toEqual({ key: 'elder/T001/1-a.jpg' });
+  });
+});
diff --git a/src/elder/elder.service.ts b/src/elder/elder.service.ts
new file mode 100644
index 0000000..f8126c6
--- /dev/null
+++ b/src/elder/elder.service.ts
@@ -0,0 +1,203 @@
+import { BadRequestException, HttpStatus, Injectable } from '@nestjs/common';
+import { BaseCrudService } from '../common/base-crud.service.js';
+import { PrismaService } from '../prisma/prisma.service.js';
+import { getRequestContext } from '../common/context/request-context.js';
+import { BusinessException } from '../common/business-exception.js';
+import { ErrorCodes } from '../common/error-codes.js';
+import { StorageService } from '../storage/storage.service.js';
+import { AuditLogsService } from '../audit-logs/audit-logs.service.js';
+import { ChangeStatusDto, CreateElderDto, ListElderQuery } from './dto.js';
+
+/**
+ * 身份证掩码：18 位 → 前4 + 10个* + 后4；15 位 → 前3 + 8个* + 后4；其余原样。
+ * 列表/非授权详情返回掩码；明文仅 admin/qc（或平台超管）可见且落审计。
+ */
+export function maskIdCard(id: string): string {
+  if (!id) return '';
+  if (id.length === 18) return `${id.slice(0, 4)}**********${id.slice(-4)}`;
+  if (id.length === 15) return `${id.slice(0, 3)}********${id.slice(-4)}`;
+  return id;
+}
+
+/** GB11643-1999 加权因子与校验码映射。 */
+const ID_WEIGHTS = [7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2];
+const ID_CHECK_CODES = ['1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2'];
+
+/** 身份证 18 位 + 校验位校验，通过返回出生日期（YYYY-MM-DD）。 */
+function deriveBirthDate(idCardNo: string): string {
+  if (!/^\d{17}[\dXx]$/.test(idCardNo)) {
+    throw new BadRequestException('身份证号格式不正确（须 18 位，末位可为 X）');
+  }
+  const sum = ID_WEIGHTS.reduce((acc, w, i) => acc + w * Number(idCardNo[i]), 0);
+  if (ID_CHECK_CODES[sum % 11] !== idCardNo[17].toUpperCase()) {
+    throw new BadRequestException('身份证号校验位错误');
+  }
+  return `${idCardNo.slice(6, 10)}-${idCardNo.slice(10, 12)}-${idCardNo.slice(12, 14)}`;
+}
+
+/** 本地今天（YYYY-MM-DD，字符串比较即日期比较）。 */
+function todayStr(): string {
+  const d = new Date();
+  const m = String(d.getMonth() + 1).padStart(2, '0');
+  const day = String(d.getDate()).padStart(2, '0');
+  return `${d.getFullYear()}-${m}-${day}`;
+}
+
+/** 建档初始状态：待遇有效期覆盖今天 → active；否则 waiting_period。 */
+function resolveInitialStatus(benefitStart?: string, benefitEnd?: string): string {
+  if (benefitStart && benefitEnd) {
+    const today = todayStr();
+    if (benefitStart <= today && today <= benefitEnd) return 'active';
+  }
+  return 'waiting_period';
+}
+
+/**
+ * 老人档案（elder）业务服务。elder 是租户级软删模型，读写经 Prisma 扩展自动注入
+ * tenantCode / deletedAt 过滤；创建时 tenantCode/createdBy 由 BaseCrudService 注入。
+ * elder_status_log 为 append-only 租户级模型（无软删），tenantCode 由本 service 显式写入。
+ */
+@Injectable()
+export class ElderService extends BaseCrudService {
+  constructor(
+    prisma: PrismaService,
+    private readonly storage: StorageService,
+    private readonly auditLogs: AuditLogsService,
+  ) {
+    super(prisma, 'elder');
+  }
+
+  /** 分页列表：状态/等级/姓名筛选；身份证服务端掩码。 */
+  async listElder(q: ListElderQuery) {
+    const where: Record<string, unknown> = {};
+    if (q.name) where.name = { contains: q.name };
+    if (q.treatStatus) where.treatStatus = q.treatStatus;
+    if (q.level) where.OR = [{ assessLevel: q.level }, { careLevel: q.level }];
+    const page = await this.paginate(q.page, q.pageSize, where);
+    return {
+      ...page,
+      list: page.list.map((e: Record<string, unknown>) => ({ ...e, idCardNo: maskIdCard(String(e.idCardNo ?? '')) })),
+    };
+  }
+
+  /**
+   * 建档：校验身份证（18 位+校验位）→ 同机构防重 → 等级与副本绑定 →
+   * 出生日期由身份证带出 → 初始状态由待遇有效期决定。
+   */
+  async createElder(dto: CreateElderDto) {
+    const idCardNo = dto.idCardNo.trim();
+    const birthDate = deriveBirthDate(idCardNo);
+    await this.assertIdCardUnique(idCardNo);
+    if ((dto.assessLevel || dto.careLevel) && !dto.assessEvidenceFile) {
+      throw new BusinessException(
+        ErrorCodes.ELDER_LEVEL_REQUIRES_EVIDENCE,
+        '填写等级须上传评估结论副本',
+        HttpStatus.BAD_REQUEST,
+      );
+    }
+    const treatStatus = resolveInitialStatus(dto.benefitStart, dto.benefitEnd);
+    // TODO(id_card_no 加密): 本期直接存明文，加密机制由后续 security change 统一落地。
+    return super.create({
+      ...dto,
+      idCardNo,
+      birthDate,
+      treatStatus,
+      statusSource: 'manual',
+    });
+  }
+
+  /** 详情：admin/qc（或平台超管）返回身份证明文并显式写审计；否则掩码。 */
+  async detail(id: string) {
+    const elder = await this.requireExists(id);
+    if (await this.canViewPlainIdCard()) {
+      const ctx = getRequestContext();
+      await this.auditLogs.record({
+        tenantCode: ctx?.tenantCode ?? '',
+        userId: ctx?.userId ?? null,
+        username: ctx?.username ?? null,
+        module: 'elder',
+        action: 'view-id-card',
+        status: 'success',
+        params: JSON.stringify({ elderId: id, elderName: elder.name }),
+      });
+      return elder;
+    }
+    return { ...elder, idCardNo: maskIdCard(String(elder.idCardNo ?? '')) };
+  }
+
+  /** 变更待遇状态：changeReason 必填；写 elder_status_log（from/to/reason/operator/changedAt）。 */
+  async changeStatus(id: string, dto: ChangeStatusDto) {
+    if (!dto.changeReason) {
+      throw new BusinessException(
+        ErrorCodes.ELDER_STATUS_REASON_REQUIRED,
+        '变更状态须填写原因',
+        HttpStatus.BAD_REQUEST,
+      );
+    }
+    const elder = await this.requireExists(id);
+    const ctx = getRequestContext();
+    const fromStatus = elder.treatStatus;
+    await this.update(id, {
+      treatStatus: dto.toStatus,
+      statusSource: 'manual',
+      statusChangeDate: new Date(),
+    });
+    await this.prisma.client.elderStatusLog.create({
+      data: {
+        elderId: id,
+        tenantCode: ctx?.tenantCode ?? '',
+        fromStatus,
+        toStatus: dto.toStatus,
+        changeReason: dto.changeReason,
+        source: 'manual',
+        operatorId: ctx?.userId ?? '',
+        evidenceFile: dto.evidenceFile ?? null,
+      },
+    });
+    return { id, fromStatus, toStatus: dto.toStatus };
+  }
+
+  /** 状态变更历史（按时间倒序）。 */
+  statusLog(id: string) {
+    const ctx = getRequestContext();
+    return this.prisma.client.elderStatusLog.findMany({
+      where: { elderId: id, tenantCode: ctx?.tenantCode },
+      orderBy: { changedAt: 'desc' },
+    });
+  }
+
+  /** 上传评估结论副本：读 buffer → StorageService.buildKey + upload → 返回 { key }。 */
+  async uploadEvidence(file: { buffer: Buffer; originalname: string }) {
+    const ctx = getRequestContext();
+    const key = this.storage.buildKey(ctx?.tenantCode ?? '', file.originalname);
+    await this.storage.upload(file.buffer, key);
+    return { key };
+  }
+
+  /** admin/qc 角色（或平台超管）可查看身份证明文。 */
+  private async canViewPlainIdCard(): Promise<boolean> {
+    const ctx = getRequestContext();
+    if (!ctx) return false;
+    if (ctx.super) return true;
+    const rows = await this.prisma.client.userRole.findMany({
+      where: { tenantCode: ctx.tenantCode, userId: ctx.userId },
+      select: { roleCode: true },
+    });
+    return rows.some((r) => r.roleCode === 'admin' || r.roleCode === 'qc');
+  }
+
+  private async assertIdCardUnique(idCardNo: string) {
+    const existing = await this.db().findFirst({ where: { idCardNo } });
+    if (existing) {
+      throw new BusinessException(ErrorCodes.ELDER_ID_CARD_EXISTS, '已有档案', HttpStatus.CONFLICT);
+    }
+  }
+
+  private async requireExists(id: string): Promise<Record<string, any>> {
+    const existing = await this.findById(id);
+    if (!existing) {
+      throw new BusinessException(ErrorCodes.ELDER_NOT_FOUND, '老人档案不存在', HttpStatus.NOT_FOUND);
+    }
+    return existing;
+  }
+}