Restyle the web UI in a light theme, step 2: remaining pages

- News: show the list and the article detail side by side; the drawer
  becomes a persistent detail panel with a revision picker and +/- line
  counts.
- Crawler console: one card per source instead of tabs, plus a merged
  live log panel filterable by source and level.
- Chat: segmented Chat / CONTEXT.md switch, message cards with times,
  bordered tool-call rows and a context usage bar.
- Login, Skills and Settings move to the panel style; diff and highlight
  colors follow the new palette. The market K-line area stays dark.

web/src/components/SkillTree.vue

@@ -127,7 +127,7 @@ function onCollapse(item: TreeItem) {
         <template #default="{ data }">
           <div
             class="group w-full flex items-center gap-1 overflow-hidden rounded pr-1 text-sm"
-            :class="{ 'opacity-50': !data.data.enabled, 'bg-yellow-100': highlightIds?.includes(data.id) }"
+            :class="{ 'opacity-50': !data.data.enabled, 'bg-amber-100': highlightIds?.includes(data.id) }"
           >
             <span>{{ data.data.kind === "folder" ? "📁" : "📄" }}</span>
             <span class="truncate">{{ data.data.name }}</span>