feat(keywords): rename brand-question terminology to search-keyword + add entity exclusion

- Rename UI/prompt labels: "品牌主问题" → "优化关键词", "搜索问题" → "搜索词"
- Add brand/competitor entity exclusion filter in question expansion (AI distill path)
- Refactor combination question text normalization, remove manual question-mark appending
- Update prompts to emphasize commercial-intent search queries over editorial phrasing
- Sync prompt changes across server/configs, deploy, and k3s configs
- Update i18n, frontend views (BrandQuestionCreate, TemplateWizard), and test fixtures

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

apps/admin-web/src/components/ArticleEditorCanvas.vue

@@ -29,6 +29,7 @@ import {
   insertHrCommand,
   toggleEmphasisCommand,
   toggleStrongCommand,
+  turnIntoTextCommand,
   wrapInBlockquoteCommand,
   wrapInBulletListCommand,
   wrapInHeadingCommand,
@@ -2266,6 +2267,7 @@ function runTableContextAction(action: TableContextMenuAction): void {
         <template #icon><IconFont type="icon-redo" /></template>
       </a-button>
       <span class="article-editor-canvas__divider"></span>
+      <a-button size="small" type="text" @click="runCommand(turnIntoTextCommand)">正文</a-button>
       <a-button size="small" type="text" @click="runCommand(wrapInHeadingCommand, 1)">H1</a-button>
       <a-button size="small" type="text" @click="runCommand(wrapInHeadingCommand, 2)">H2</a-button>
       <a-button size="small" type="text" @click="runCommand(wrapInHeadingCommand, 3)">H3</a-button>