theme: 以 feature/theme-remote-p0 内容整体替换 main（主题通道化试点，非 merge）

- 本地 icons.css/layout.css 下线改走中央静态通道；新增 ThemeSwitcher.vue + useElementHeight.ts；
  layout/main.ts/vite/menu 及各页适配对齐 feature 试点。
- 已知回退：本轮按 feature 覆盖，冲掉了 main 上 31ca694(/approval 可达性+modId 对齐) 与
  1516eff(cc useTableHeight) 两处功能修复，待后续单独补回。
- 回滚锚点：archive/main-before-theme-20260924 = 替换前 main(1516eff)。

package-lock.json

@@ -33,6 +33,7 @@
                 "@unocss/preset-rem-to-px": "^66.6.0",
                 "@unocss/preset-uno": "^66.6.0",
                 "@vitejs/plugin-vue": "^5.0.4",
+                "@yunhai/vite-plugin-theme": "file:../../YschTheme/packages/vite-plugin",
                 "fast-glob": "^3.3.2",
                 "typescript": "^5.2.2",
                 "unocss": "^66.6.0",
@@ -43,6 +44,20 @@
                 "vue-tsc": "^1.8.27"
             }
         },
+        "../../YschTheme/packages/vite-plugin": {
+            "name": "@yunhai/vite-plugin-theme",
+            "version": "0.1.0",
+            "dev": true,
+            "license": "UNLICENSED",
+            "devDependencies": {
+                "tsup": "^8.3.5",
+                "typescript": "^5.2.2",
+                "vite": "^5.1.4"
+            },
+            "peerDependencies": {
+                "vite": ">=4.0.0"
+            }
+        },
         "node_modules/@alova/shared": {
             "version": "1.3.4",
             "resolved": "https://registry.npmmirror.com/@alova/shared/-/shared-1.3.4.tgz",
@@ -2576,6 +2591,10 @@
                 "node": ">=10.0.0"
             }
         },
+        "node_modules/@yunhai/vite-plugin-theme": {
+            "resolved": "../../YschTheme/packages/vite-plugin",
+            "link": true
+        },
         "node_modules/acorn": {
             "version": "8.18.0",
             "resolved": "https://registry.npmmirror.com/acorn/-/acorn-8.18.0.tgz",