feat(front-end): 依据《详细设计》文档对前端 UI 进行全面升级

- 设计系统：品牌主色统一为品红渐变 #c2185b→#e91e63，新增品牌令牌与呼吸/入场动画
- 登录页重建：内部员工/外部账号切换、账号/手机验证码 Tab、SRM 存量提示
- 注册页重建为多步向导：企业信息→联系人→AI 审核，OCR 状态、密码复杂度校验与强度条
- 小滨 AI 助手重建：品牌渐变悬浮球+呼吸光环，角色感知主动提醒（紧急/AI完成/待办/风险/建议）
- 新增公开门户首页 /portal：Banner 轮播 + 三列公告区 + 免责声明
- 各角色主题色对齐文档：供应商=红、评标专家=蓝、招标专员=绿

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

front-end/src/app/roles.ts

@@ -48,9 +48,9 @@ export const ROLES: Record<RoleId, RoleConfig> = {
     name: "招标专员",
     user: "张伟",
     dept: "招标采购中心",
-    color: "#2563eb",
-    bannerFrom: "#0f1e3d",
-    bannerTo: "#2563eb",
+    color: "#00695c",
+    bannerFrom: "#00695c",
+    bannerTo: "#00897b",
     nav: [
       { to: "/app", label: "工作台", icon: "LayoutDashboard", end: true },
       { to: "/app/projects", label: "项目管理", icon: "FolderKanban" },
@@ -82,9 +82,9 @@ export const ROLES: Record<RoleId, RoleConfig> = {
     name: "评标专家",
     user: "郑国华",
     dept: "外部专家 · 化工工艺",
-    color: "#f59e0b",
-    bannerFrom: "#7c2d12",
-    bannerTo: "#f59e0b",
+    color: "#1565c0",
+    bannerFrom: "#0d47a1",
+    bannerTo: "#1976d2",
     nav: [
       { to: "/app", label: "工作台", icon: "LayoutDashboard", end: true },
       { to: "/app/expert-tasks", label: "评标任务", icon: "Gavel" },
@@ -121,9 +121,9 @@ export const ROLES: Record<RoleId, RoleConfig> = {
     name: "供应商",
     user: "浙江中控技术股份有限公司",
     dept: "投标用户",
-    color: "#8b5cf6",
-    bannerFrom: "#4c1d95",
-    bannerTo: "#8b5cf6",
+    color: "#c2185b",
+    bannerFrom: "#c2185b",
+    bannerTo: "#e91e63",
     nav: [
       { to: "/app", label: "工作台", icon: "LayoutDashboard", end: true },
       { to: "/app/bidding", label: "投标中心", icon: "PackageOpen" },