refactor(monitoring): simplify brand dashboard and harden citation rendering

- drop brand_time_buckets and sparkline/coverage UI; dashboard now returns a single day
- compute mention rate from total actual samples instead of averaging per-platform rates
- canonicalize ai_platform_id across services and aggregate platform-overview snapshots
- strip mojibake and non-answer noise from callback payloads and question detail answers
- keep Kimi citations panel-only; still store raw search_results for audit
- render linked [n] inline citations for qwen/yuanbao answers with scroll-to-source behavior
- restrict立即采集 to today's business date with a clear i18n hint
- refresh content-citations into an ant-design table with truncation and hover styling

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/admin-web/src/i18n/messages/en-US.ts

@@ -348,6 +348,7 @@ const enUS = {
     collectNow: "Collect Now",
     collectBrandRequired: "Select a brand before collecting.",
     collectKeywordRequired: "Select a keyword before collecting the current question set.",
+    collectTodayOnly: "Collect Now only supports today's data. Switch back to today to continue.",
     collectClientChecking: "Checking whether the current account's desktop client is online.",
     collectClientOnlineRequired: "The current account's desktop client must be online before collecting.",
     pluginMode: "Plugin sampling",