✨ feat: 添加结构化日志支持并优化错误处理

- 在 netlify/functions/_shared/server-logger.js 中重构日志函数，统一日志输出格式，支持 context 字段覆盖基础字段（如 message）
- 在 netlify/functions/_shared/middleware.js 中增强 withAuth 中间件，注入结构化 logger 到上下文，增加 request_start / request_end / request_error 日志追踪，并记录请求耗时
- 为所有 Netlify Function（giffgaff-sms-activate、giffgaff-graphql、auto-activate-esim、verify-cookie、giffgaff-token-exchange、giffgaff-mfa-challenge、giffgaff-mfa-validation、health）添加结构化日志，替换原有 console 输出，包含请求入参、状态和耗时
- 在 netlify/edge-functions/bff-proxy.js 和 markdown-negotiation.js 中实现 Deno 内联结构化日志，生成 requestId 并统一日志输出格式，支持 INFO/WARN/ERROR/DEBUG 级别控制
- 更新测试用例 tests/modules/server-logger.test.js 和 tests/functions/middleware-logging.test.js，新增日志级别过滤、context 覆盖、多实例隔离、OPTIONS 预检处理等测试场景

tests/functions/middleware-logging.test.js

@@ -131,14 +131,14 @@ describe('withAuth 日志集成', () => {
       { httpMethod: 'GET', path: '/a', headers: { origin: 'https://esim.cosr.eu.org' } },
       { functionName: 'fn1' }
     );
-    const reqId1 = mockLogs[0]?.ctx?.requestId;
+    const reqId1 = mockLogs[0]?.reqId;
 
     mockLogs.length = 0;
     await wrapped(
       { httpMethod: 'GET', path: '/b', headers: { origin: 'https://esim.cosr.eu.org' } },
       { functionName: 'fn2' }
     );
-    const reqId2 = mockLogs[0]?.ctx?.requestId;
+    const reqId2 = mockLogs[0]?.reqId;
 
     expect(reqId1).toBeDefined();
     expect(reqId2).toBeDefined();
@@ -156,4 +156,97 @@ describe('withAuth 日志集成', () => {
 
     expect(createLogger).toHaveBeenCalledWith('my-function', expect.any(String));
   });
+
+  it('CORS 鉴权失败时应该输出 request_error 日志', async () => {
+    const mockHandler = jest.fn(async () => ({ statusCode: 200, body: '{}' }));
+    const wrapped = withAuth(mockHandler, { requireAuth: false });
+
+    await wrapped(
+      { httpMethod: 'GET', path: '/bff/test', headers: { origin: 'https://evil.com' } },
+      { functionName: 'test-fn' }
+    );
+
+    const errorLog = mockLogs.find((l) => l.msg === 'request_error');
+    expect(errorLog).toBeDefined();
+    expect(errorLog.ctx.status).toBe(403);
+    expect(errorLog.ctx.errorName).toBe('AuthError');
+    // handler 不应被调用
+    expect(mockHandler).not.toHaveBeenCalled();
+  });
+
+  it('无效 JSON body 时应该输出 request_error 日志', async () => {
+    const mockHandler = jest.fn(async () => ({ statusCode: 200, body: '{}' }));
+    const wrapped = withAuth(mockHandler, { requireAuth: false });
+
+    await wrapped(
+      {
+        httpMethod: 'POST',
+        path: '/bff/test',
+        headers: { origin: 'https://esim.cosr.eu.org' },
+        body: 'not-valid-json{{{',
+      },
+      { functionName: 'test-fn' }
+    );
+
+    const errorLog = mockLogs.find((l) => l.msg === 'request_error');
+    expect(errorLog).toBeDefined();
+    expect(errorLog.ctx.status).toBe(400);
+    expect(errorLog.ctx.errorMessage).toBe('Invalid JSON body');
+    expect(mockHandler).not.toHaveBeenCalled();
+  });
+
+  it('输入验证失败时应该输出 request_error 日志', async () => {
+    const mockHandler = jest.fn(async () => ({ statusCode: 200, body: '{}' }));
+    const schema = { name: { required: true, type: 'string' } };
+    const wrapped = withAuth(mockHandler, { requireAuth: false, validateSchema: schema });
+
+    await wrapped(
+      {
+        httpMethod: 'POST',
+        path: '/bff/test',
+        headers: { origin: 'https://esim.cosr.eu.org' },
+        body: JSON.stringify({}),
+      },
+      { functionName: 'test-fn' }
+    );
+
+    const errorLog = mockLogs.find((l) => l.msg === 'request_error');
+    expect(errorLog).toBeDefined();
+    expect(errorLog.ctx.status).toBe(400);
+    expect(errorLog.ctx.errorMessage).toMatch(/name is required/);
+    expect(mockHandler).not.toHaveBeenCalled();
+  });
+
+  it('error 日志应包含耗时字段', async () => {
+    const mockHandler = jest.fn(async () => {
+      throw new Error('slow fail');
+    });
+    const wrapped = withAuth(mockHandler, { requireAuth: false });
+
+    await wrapped(
+      { httpMethod: 'GET', path: '/bff/test', headers: { origin: 'https://esim.cosr.eu.org' } },
+      { functionName: 'test-fn' }
+    );
+
+    const errorLog = mockLogs.find((l) => l.msg === 'request_error');
+    expect(errorLog.ctx.duration).toBeDefined();
+    expect(typeof errorLog.ctx.duration).toBe('number');
+    expect(errorLog.ctx.duration).toBeGreaterThanOrEqual(0);
+  });
+
+  it('OPTIONS 预检请求不输出 request_start 日志（提前返回）', async () => {
+    const mockHandler = jest.fn(async () => ({ statusCode: 200, body: '{}' }));
+    const wrapped = withAuth(mockHandler, { requireAuth: false });
+
+    await wrapped(
+      { httpMethod: 'OPTIONS', path: '/bff/test', headers: { origin: 'https://esim.cosr.eu.org' } },
+      { functionName: 'test-fn' }
+    );
+
+    // request_start 仍然会输出（在鉴权之前），但 request_end 不会（预检提前返回）
+    const startLog = mockLogs.find((l) => l.msg === 'request_start');
+    expect(startLog).toBeDefined();
+    // handler 不应被调用
+    expect(mockHandler).not.toHaveBeenCalled();
+  });
 });

tests/modules/server-logger.test.js

@@ -51,6 +51,25 @@ describe('server-logger', () => {
       expect(output.duration).toBe(42);
     });
 
+    it('context 为 null 或 undefined 时不应报错', () => {
+      const logger = createLogger('test-fn', 'req-1');
+      expect(() => logger.info('msg', null)).not.toThrow();
+      expect(() => logger.info('msg', undefined)).not.toThrow();
+      expect(() => logger.warn('msg', null)).not.toThrow();
+      expect(() => logger.error('msg', null)).not.toThrow();
+      const output = JSON.parse(consoleSpy.log.mock.calls[0][0]);
+      expect(output.message).toBe('msg');
+      expect(output.requestId).toBe('req-1');
+    });
+
+    it('context 中同名字段应覆盖基础字段（Object.assign 语义）', () => {
+      const logger = createLogger('test-fn', 'req-1');
+      logger.info('override test', { message: 'overridden' });
+      const output = JSON.parse(consoleSpy.log.mock.calls[0][0]);
+      // Object.assign 后 context 中的 message 覆盖基础字段
+      expect(output.message).toBe('overridden');
+    });
+
     it('warn 应该输出到 console.warn', () => {
       const logger = createLogger('test-fn', 'req-1');
       logger.warn('warning msg');
@@ -88,6 +107,50 @@ describe('server-logger', () => {
       if (originalLevel) process.env.LOG_LEVEL = originalLevel;
       else delete process.env.LOG_LEVEL;
     });
+
+    it('LOG_LEVEL=ERROR 时应该抑制 INFO 和 WARN', () => {
+      const originalLevel = process.env.LOG_LEVEL;
+      process.env.LOG_LEVEL = 'ERROR';
+      const logger = createLogger('test-fn', 'req-1');
+      logger.info('should not appear');
+      logger.warn('should not appear');
+      expect(consoleSpy.log).not.toHaveBeenCalled();
+      expect(consoleSpy.warn).not.toHaveBeenCalled();
+      // ERROR 仍然输出
+      logger.error('should appear');
+      expect(consoleSpy.error).toHaveBeenCalledTimes(1);
+      if (originalLevel) process.env.LOG_LEVEL = originalLevel;
+      else delete process.env.LOG_LEVEL;
+    });
+
+    it('LOG_LEVEL=WARN 时应该抑制 INFO 和 DEBUG', () => {
+      const originalLevel = process.env.LOG_LEVEL;
+      process.env.LOG_LEVEL = 'WARN';
+      const logger = createLogger('test-fn', 'req-1');
+      logger.info('should not appear');
+      logger.debug('should not appear');
+      expect(consoleSpy.log).not.toHaveBeenCalled();
+      // WARN 和 ERROR 仍然输出
+      logger.warn('should appear');
+      logger.error('should appear');
+      expect(consoleSpy.warn).toHaveBeenCalledTimes(1);
+      expect(consoleSpy.error).toHaveBeenCalledTimes(1);
+      if (originalLevel) process.env.LOG_LEVEL = originalLevel;
+      else delete process.env.LOG_LEVEL;
+    });
+
+    it('多个 logger 实例应该互不干扰', () => {
+      const logger1 = createLogger('fn-a', 'req-1');
+      const logger2 = createLogger('fn-b', 'req-2');
+      logger1.info('from a');
+      logger2.info('from b');
+      const out1 = JSON.parse(consoleSpy.log.mock.calls[0][0]);
+      const out2 = JSON.parse(consoleSpy.log.mock.calls[1][0]);
+      expect(out1.function).toBe('fn-a');
+      expect(out1.requestId).toBe('req-1');
+      expect(out2.function).toBe('fn-b');
+      expect(out2.requestId).toBe('req-2');
+    });
   });
 
   describe('parseLogLevel', () => {