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/views/TrackingView.vue

@@ -862,7 +862,7 @@ function disableTrackingDate(current: dayjs.Dayjs): boolean {
             />
           </div>
           <div class="tracking-action-item">
-            <span class="tracking-action-label">问题集</span>
+            <span class="tracking-action-label">关键词库（搜索词）</span>
             <a-select
               v-model:value="selectedQuestionSetOptionValue"
               show-search