chore: upgrade vuepress to rc.30 and theme-hope to rc.107 (rolldown) (#1138)

Switch @vuepress/bundler-vite to the rolldown-driven build path and
align the @vuepress/* plugins / helper to rc.130. theme-hope rc.107
also removes temp pages, which is the bulk of the time/memory win.

Version changes:
- vuepress / @vuepress/bundler-vite: rc.26 -> rc.30
- vuepress-theme-hope: rc.99 -> rc.107
- @vuepress/plugin-docsearch / plugin-links-check / helper /
  plugin-back-to-top: rc.120 -> rc.130
- sass-embedded: 1.93.3 -> 1.100.0 (required for theme-hope rc.107's
  new `if(sass(...): ...; else: ...)` SCSS syntax)

Local build benchmark (pnpm run build, /usr/bin/time -l):
- Before (rc.26):  112.30s build, peak RSS 6731 MB
- After  (rc.30):   58.67s build, peak RSS 5254 MB
- Wins: -47.8% build time, -21.9% peak RSS

Removes the CI build OOM risk on the 8 GB node heap without needing
to raise --max_old_space_size, and roughly halves the build wall time.

No source changes; only dependency versions and lockfile.

Author: CritasWang

package.json

@@ -22,20 +22,20 @@
   },
   "dependencies": {
     "@element-plus/icons-vue": "^2.3.2",
-    "@vuepress/bundler-vite": "2.0.0-rc.26",
-    "@vuepress/plugin-docsearch": "2.0.0-rc.120",
-    "@vuepress/plugin-links-check": "2.0.0-rc.120",
+    "@vuepress/bundler-vite": "2.0.0-rc.30",
+    "@vuepress/plugin-docsearch": "2.0.0-rc.130",
+    "@vuepress/plugin-links-check": "2.0.0-rc.130",
     "element-plus": "^2.12.0",
-    "sass-embedded": "1.93.3",
+    "sass-embedded": "1.100.0",
     "vue": "^3.5.25",
     "vue3-carousel": "0.17.0",
-    "vuepress": "2.0.0-rc.26",
-    "vuepress-theme-hope": "2.0.0-rc.99"
+    "vuepress": "2.0.0-rc.30",
+    "vuepress-theme-hope": "2.0.0-rc.107"
   },
   "devDependencies": {
     "@eslint/js": "9.39.1",
-    "@vuepress/helper": "2.0.0-rc.120",
-    "@vuepress/plugin-back-to-top": "2.0.0-rc.120",
+    "@vuepress/helper": "2.0.0-rc.130",
+    "@vuepress/plugin-back-to-top": "2.0.0-rc.130",
     "eslint": "9.39.1",
     "eslint-plugin-vue": "10.6.2",
     "gh-pages": "6.3.0",