feat(design): 主色改靛蓝 #4F46E5，Web 与安卓及 Logo 同步

- primary 换成 Indigo 阶（600 即 #4F46E5），中性色转 Slate 轴、纸面更冷更白
- 实心主色面（主按钮、工作区选中）用 600，链接/浅底文字仍用 700 保对比度
- 信息色 sky 调深到 #16697C，与靛蓝同屏能分清
- Logo / favicon / PWA 图标 / 安卓自适应图标统一为靛蓝底 + 白线 + 淡紫点，tools/make-icons.py 重新生成
- 文档与 e2e 断言同步（主题色 #4f46e5）

web/tailwind.config.js

@@ -4,44 +4,44 @@ export default {
   theme: {
     extend: {
       colors: {
-        // 底色：暖白纸面，不用纯白，避免刺眼、也让卡片有层次
+        // 底色：近白的冷调纸面，不用纯白，避免刺眼、也让卡片有层次
         paper: {
-          50: "#F9FAFC",
-          100: "#F3F5F9",
-          200: "#E9EDF3",
-          300: "#DFE5ED",
+          50: "#FAFAFC",
+          100: "#F4F5F9",
+          200: "#EBEDF3",
+          300: "#E0E4EC",
         },
-        // 分隔线与描边（冷灰，跟蓝主色同一个中性轴）
+        // 分隔线与描边（冷灰，跟靛蓝同一个中性轴）
         line: {
-          100: "#EDEFF3",
-          200: "#E2E6EC",
-          300: "#D3D9E1",
+          100: "#EEF0F5",
+          200: "#E3E7EF",
+          300: "#D5DAE4",
         },
-        // 文字与中性
+        // 文字与中性（Slate 轴：比纯灰更冷一点，和靛蓝同屏不打架）
         ink: {
           50: "#F6F8FA",
           100: "#E9EEF3",
           200: "#D7DEE7",
           300: "#B8C2CE",
-          400: "#929EAD",
-          500: "#5F6B7C",
-          600: "#4E5867",
-          700: "#3A4352",
-          800: "#262D39",
-          900: "#161C25",
+          400: "#94A3B8",
+          500: "#64748B",
+          600: "#475569",
+          700: "#334155",
+          800: "#1E293B",
+          900: "#0F172A",
         },
-        // 主色：景泰蓝（沉一点的靛蓝），克制、有"工作台"气质，避开任务工具常见的荧光蓝
+        // 主色：靛蓝 #4F46E5（Indigo 600）。饱和度足、明度高，压在按钮/链接/选中态上不发灰。
         primary: {
-          50: "#EFF5FB",
-          100: "#DCE9F7",
-          200: "#B9D3EC",
-          300: "#8FB6DD",
-          400: "#6094C8",
-          500: "#3E76AC",
-          600: "#2E5D8D",
-          700: "#274B73",
-          800: "#1F3B5B",
-          900: "#1A2F48",
+          50: "#EEF2FF",
+          100: "#E0E7FF",
+          200: "#C7D2FE",
+          300: "#A5B4FC",
+          400: "#818CF8",
+          500: "#6366F1",
+          600: "#4F46E5",
+          700: "#4338CA",
+          800: "#3730A3",
+          900: "#312E81",
         },
         // 强调色：陶土橙，只用在"需要人注意"的地方
         clay: {
@@ -59,8 +59,8 @@ export default {
         sage: { 500: "#2F7D5E", 50: "#EAF4EF" },
         wheat: { 500: "#A97C25", 50: "#F8F1E2" },
         rust: { 500: "#B04A32", 50: "#FAEDE9" },
-        // 信息色：往青绿方向拉开一档，和 primary 的「进行中」在同一屏里也能分清
-        sky: { 500: "#1E7F94", 50: "#E6F4F6" },
+        // 信息色：往青绿方向拉开一大档，和靛蓝主色在同一屏里一眼分得清
+        sky: { 500: "#16697C", 50: "#E6F4F6" },
       },
       fontFamily: {
         sans: [
@@ -94,8 +94,8 @@ export default {
         "3xl": "24px",
       },
       boxShadow: {
-        card: "0 1px 2px rgba(20,27,36,0.04), 0 8px 24px -16px rgba(20,27,36,0.35)",
-        pop: "0 2px 6px rgba(20,27,36,0.06), 0 20px 48px -24px rgba(20,27,36,0.35)",
+        card: "0 1px 2px rgba(15,23,42,0.04), 0 8px 24px -16px rgba(15,23,42,0.30)",
+        pop: "0 2px 6px rgba(15,23,42,0.06), 0 20px 48px -24px rgba(15,23,42,0.32)",
         inset: "inset 0 1px 0 rgba(255,255,255,0.6)",
       },
       keyframes: {