feat: 双主题系统 — 编辑风 + 极简亮色

前端:
- 新增 Pinia theme store，localStorage 持久化，data-theme 切换
- App.vue: :root 新增 --font-*/--sidebar-* CSS 变量；新增 :root[data-theme=light] 完整配色（极简黑白金 + Noto Sans SC）
- DesktopLayout: 侧边栏 15 个变量化 + 顶栏主题切换按钮
- MobileLayout: 装饰色变量化
- Settings: 新增「界面主题」卡片
- 21 个组件 font-family 统一替换为 var(--font-*)
- 新增 utils/managerColor.ts — 12 色调色板 + 自适应文字色 + 后端自定义色优先
- WorkPlans/MiniBusiness/KeyVisits/CustomerManage: 客户经理标签色统一走共享工具
- UserManage: 编辑弹窗新增颜色选择器（仅 manager）
- LightBoard: 去标题星标图标
- ManagerWorkspace/WorkPlans/MiniBusiness/KeyVisits: 删除按钮改为实心红底白字

后端:
- User 模型新增 color 列 + lifespan 自动迁移
- users API 支持 color 字段读写
- UserOut schema 新增 color

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/src/App.vue

@@ -67,6 +67,114 @@ const isMobile = computed(() => {
   --radius-sm: 2px;
   --radius-xs: 2px;
   --transition: 0.22s cubic-bezier(0.4, 0, 0.2, 1);
+
+  /* ── Sidebar — dark editorial ── */
+  --sidebar-bg: var(--ink);
+  --sidebar-color: #fff;
+  --sidebar-accent: var(--gold);
+  --sidebar-nav-text: rgba(255,255,255,0.55);
+  --sidebar-nav-text-hover: rgba(255,255,255,0.85);
+  --sidebar-nav-text-active: #fff;
+  --sidebar-nav-bg-hover: rgba(255,255,255,0.04);
+  --sidebar-nav-bg-active: rgba(255,255,255,0.06);
+  --sidebar-nav-border-active: var(--gold);
+  --sidebar-divider: rgba(255,255,255,0.06);
+  --sidebar-brand-color: #fff;
+  --sidebar-brand-sub-color: rgba(255,255,255,0.4);
+  --sidebar-group-label-color: rgba(255,255,255,0.25);
+  --sidebar-footer-role-color: var(--gold);
+  --sidebar-footer-name-color: rgba(255,255,255,0.7);
+
+  /* ── Mobile page accent ── */
+  --page-accent-color: rgba(196,147,74,0.06);
+
+  /* ── Manager chip tags ── */
+  --mgr-chip-text: #fff;
+
+  /* ── Fonts — editorial Chinese ── */
+  --font-body: 'Noto Serif SC', STSong, Songti SC, '宋体', serif;
+  --font-heading: 'ZCOOL XiaoWei', STSong, Songti SC, serif;
+  --font-mono: 'JetBrains Mono', 'SF Mono', monospace;
+}
+
+/* ═══════════════════════════════════════════════════════════
+   THEME: Light — 极简功能主义 / Brutally Minimal
+   ═══════════════════════════════════════════════════════════ */
+
+:root[data-theme="light"] {
+  /* ── Core palette ── */
+  --ink: #1A1A1A;
+  --ink-light: #3D3D3D;
+  --ink-dark: #0A0A0A;
+  --vermilion: #DC2626;
+  --vermilion-light: #EF4444;
+  --vermilion-dark: #B91C1C;
+  --gold: #D4AF37;
+  --gold-light: #E5C955;
+  --gold-dark: #B8941F;
+  --paper: #F5F5F5;
+  --paper-dark: #EBEBEB;
+  --surface: #FFFFFF;
+  --sage: #16A34A;
+  --amber: #D97706;
+  --warm-gray: #666666;
+  --warm-border: #DDDDDD;
+
+  /* ── Semantic tokens ── */
+  --c-primary: var(--ink);
+  --c-primary-light: var(--ink-light);
+  --c-primary-bg: #F5F5F5;
+  --c-accent: var(--vermilion);
+  --c-accent-light: var(--vermilion-light);
+  --c-gold: var(--gold);
+  --c-success: var(--sage);
+  --c-warning: var(--amber);
+  --c-danger: var(--vermilion);
+  --c-info: #2563EB;
+  --c-text: #1A1A1A;
+  --c-text-secondary: #666666;
+  --c-text-muted: #999999;
+  --c-bg: var(--paper);
+  --c-bg-card: var(--surface);
+  --c-border: var(--warm-border);
+
+  /* ── Effects ── */
+  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
+  --shadow: 0 1px 3px rgba(0,0,0,0.08);
+  --shadow-md: 0 2px 6px rgba(0,0,0,0.10);
+  --shadow-lg: 0 4px 12px rgba(0,0,0,0.12);
+  --radius: 0px;
+  --radius-sm: 0px;
+  --radius-xs: 0px;
+  --transition: 0.18s cubic-bezier(0.4, 0, 0.2, 1);
+
+  /* ── Sidebar — light minimal ── */
+  --sidebar-bg: #FFFFFF;
+  --sidebar-color: #1A1A1A;
+  --sidebar-accent: var(--gold);
+  --sidebar-nav-text: #777777;
+  --sidebar-nav-text-hover: #1A1A1A;
+  --sidebar-nav-text-active: #1A1A1A;
+  --sidebar-nav-bg-hover: #F5F5F5;
+  --sidebar-nav-bg-active: #F0F0F0;
+  --sidebar-nav-border-active: var(--gold);
+  --sidebar-divider: #EEEEEE;
+  --sidebar-brand-color: #1A1A1A;
+  --sidebar-brand-sub-color: #999999;
+  --sidebar-group-label-color: #AAAAAA;
+  --sidebar-footer-role-color: var(--gold);
+  --sidebar-footer-name-color: #777777;
+
+  /* ── Mobile page accent ── */
+  --page-accent-color: rgba(212,175,55,0.04);
+
+  /* ── Manager chip tags ── */
+  --mgr-chip-text: #1A1A1A;
+
+  /* ── Fonts — sans-serif minimal ── */
+  --font-body: 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
+  --font-heading: 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
+  --font-mono: 'JetBrains Mono', monospace;
 }
 
 /* ── Reset & Base ── */
@@ -76,7 +184,7 @@ html, body, #app {
   margin: 0; padding: 0; height: 100%;
   overflow-x: hidden;
   -webkit-overflow-scrolling: touch;
-  font-family: 'Noto Serif SC', STSong, Songti SC, '宋体', serif;
+  font-family: var(--font-body);
   font-size: 15px;
   line-height: 1.7;
   color: var(--c-text);
@@ -87,7 +195,7 @@ html, body, #app {
 
 /* ── Editorial heading style ── */
 h1, h2, h3, h4, h5, h6 {
-  font-family: 'ZCOOL XiaoWei', STSong, Songti SC, serif;
+  font-family: var(--font-heading);
   letter-spacing: 0.02em;
 }
 
@@ -107,7 +215,7 @@ h1, h2, h3, h4, h5, h6 {
 .el-card__header {
   border-bottom: 2px solid var(--gold) !important;
   padding: 16px 20px !important;
-  font-family: 'ZCOOL XiaoWei', STSong, serif;
+  font-family: var(--font-heading);
   font-weight: 600;
   font-size: 16px;
   color: var(--ink);
@@ -121,7 +229,7 @@ h1, h2, h3, h4, h5, h6 {
   font-weight: 500;
   letter-spacing: 0.02em;
   transition: all var(--transition);
-  font-family: 'Noto Serif SC', STSong, Songti SC, serif;
+  font-family: var(--font-body);
 }
 .el-button--primary {
   background: var(--ink) !important;
@@ -149,14 +257,14 @@ h1, h2, h3, h4, h5, h6 {
 .el-tag {
   border-radius: 2px !important;
   font-weight: 500;
-  font-family: 'Noto Serif SC', STSong, serif;
+  font-family: var(--font-body);
   letter-spacing: 0.02em;
 }
 
 /* ── Tabs ── */
 .el-tabs__item {
   font-weight: 500;
-  font-family: 'ZCOOL XiaoWei', STSong, serif;
+  font-family: var(--font-heading);
 }
 .el-tabs__active-bar { background: var(--gold) !important; }
 .el-tabs__item.is-active { color: var(--ink) !important; }
@@ -167,7 +275,7 @@ h1, h2, h3, h4, h5, h6 {
   color: var(--ink);
   font-weight: 600;
   font-size: 13px;
-  font-family: 'ZCOOL XiaoWei', STSong, serif;
+  font-family: var(--font-heading);
   letter-spacing: 0.03em;
 }
 .el-table--striped .el-table__body tr.el-table__row--striped td.el-table__cell {
@@ -184,7 +292,7 @@ h1, h2, h3, h4, h5, h6 {
 .el-dialog__header {
   padding: 20px 24px 0 !important;
   font-weight: 600;
-  font-family: 'ZCOOL XiaoWei', STSong, serif;
+  font-family: var(--font-heading);
 }
 .el-dialog__body { padding: 20px 24px !important; }
 
@@ -225,7 +333,7 @@ h1, h2, h3, h4, h5, h6 {
 /* ── Textarea ── */
 .el-textarea__inner {
   border-radius: 2px !important;
-  font-family: 'Noto Serif SC', STSong, serif;
+  font-family: var(--font-body);
 }
 
 /* ── Radio ── */
@@ -258,7 +366,7 @@ h1, h2, h3, h4, h5, h6 {
 
 /* ── Divider ── */
 .el-divider__text {
-  font-family: 'ZCOOL XiaoWei', STSong, serif;
+  font-family: var(--font-heading);
   color: var(--warm-gray);
 }