feat(web): 登录页主题适配 + 工作台角色化重构

- 登录页接入 4 套主题系统（渐变色/面板背景/文字色），添加 ThemeSwitcher
- 工作台按角色（医生/护士/管理员/运营）显示专属统计卡片和快捷入口
- 移除系统信息填充卡片，硬编码颜色替换为 CSS 变量

apps/web/src/index.css

@@ -265,6 +265,166 @@
   --erp-font-heading: 'Noto Sans SC', -apple-system, system-ui, sans-serif;
 }
 
+/* --- Login Page Tokens --- */
+:root {
+  --login-gradient-start: #312E81;
+  --login-gradient-mid: #2563eb;
+  --login-gradient-end: #60a5fa;
+  --login-form-bg: #ffffff;
+  --login-form-text: #0f172a;
+  --login-form-text-secondary: #475569;
+  --login-input-icon-color: #94a3b8;
+}
+
+[data-theme='warm'] {
+  --login-gradient-start: #6B3418;
+  --login-gradient-mid: #C4623A;
+  --login-gradient-end: #D4956A;
+  --login-form-bg: #FAF5F0;
+  --login-form-text: #2D2A26;
+  --login-form-text-secondary: #7A756E;
+  --login-input-icon-color: #A8A29E;
+}
+
+[data-theme='dark'] {
+  --login-gradient-start: #0F172A;
+  --login-gradient-mid: #1E293B;
+  --login-gradient-end: #334155;
+  --login-form-bg: #1E293B;
+  --login-form-text: rgba(255,255,255,0.95);
+  --login-form-text-secondary: #94A3B8;
+  --login-input-icon-color: #64748B;
+}
+
+[data-theme='emerald'] {
+  --login-gradient-start: #2D4A2F;
+  --login-gradient-mid: #5B7A5E;
+  --login-gradient-end: #8FB092;
+  --login-form-bg: #F4F7F4;
+  --login-form-text: #1A2E1A;
+  --login-form-text-secondary: #5A6E5A;
+  --login-input-icon-color: #8FA08F;
+}
+
+/* --- Login Page Styles --- */
+.login-root {
+  display: flex;
+  min-height: 100vh;
+}
+
+.login-brand-panel {
+  flex: 1;
+  background: linear-gradient(135deg, var(--login-gradient-start) 0%, var(--login-gradient-mid) 50%, var(--login-gradient-end) 100%);
+  display: flex;
+  flex-direction: column;
+  justify-content: center;
+  align-items: center;
+  padding: 60px;
+  position: relative;
+  overflow: hidden;
+}
+
+.login-brand-panel .deco-circle {
+  position: absolute;
+  border-radius: 50%;
+  background: rgba(255, 255, 255, 0.05);
+}
+
+.login-brand-panel .brand-icon {
+  width: 64px;
+  height: 64px;
+  border-radius: 16px;
+  background: rgba(255, 255, 255, 0.15);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  margin: 0 auto 32px;
+  backdrop-filter: blur(8px);
+  border: 1px solid rgba(255, 255, 255, 0.2);
+}
+
+.login-brand-panel .brand-icon .anticon {
+  font-size: 32px;
+  color: #fff;
+}
+
+.login-brand-panel .brand-title {
+  color: #fff;
+  font-size: 36px;
+  font-weight: 800;
+  margin: 0 0 16px;
+  letter-spacing: -1px;
+  line-height: 1.2;
+}
+
+.login-brand-panel .brand-desc {
+  color: rgba(255, 255, 255, 0.7);
+  font-size: 16px;
+  line-height: 1.6;
+  margin: 0;
+}
+
+.login-brand-panel .brand-sub-desc {
+  color: rgba(255, 255, 255, 0.5);
+  font-size: 14px;
+  line-height: 1.6;
+  margin-top: 8px;
+}
+
+.login-brand-panel .feature-item-value {
+  color: rgba(255, 255, 255, 0.9);
+  font-size: 18px;
+  font-weight: 700;
+}
+
+.login-brand-panel .feature-item-label {
+  color: rgba(255, 255, 255, 0.5);
+  font-size: 12px;
+  margin-top: 4px;
+}
+
+.login-form-panel {
+  width: 480px;
+  display: flex;
+  flex-direction: column;
+  justify-content: center;
+  padding: 60px;
+  background: var(--login-form-bg);
+  position: relative;
+  transition: background var(--erp-transition-slow);
+}
+
+.login-form-panel .form-title {
+  margin-bottom: 4px;
+  font-weight: 700;
+  font-size: 24px;
+  color: var(--login-form-text);
+}
+
+.login-form-panel .form-subtitle {
+  font-size: 14px;
+  color: var(--login-form-text-secondary);
+}
+
+.login-form-panel .form-footer {
+  margin-top: 32px;
+  text-align: center;
+  font-size: 12px;
+  color: var(--login-form-text-secondary);
+}
+
+.login-theme-switcher {
+  position: absolute;
+  top: 20px;
+  right: 20px;
+  z-index: 10;
+}
+
+.login-theme-switcher .erp-header-btn {
+  background: var(--login-form-bg);
+  border: 1px solid var(--erp-border);
+  color: var(--login-form-text-secondary);
+}
 
 /* --- Global Reset & Base --- */
 body {