fix(ai-advice,ui): Bearer auth for proxy gateways + un-pin contact card + VN diacritics

- AI advice handler now sends both `x-api-key` and `Authorization: Bearer`
  so proxy gateways (e.g. chat.trollllm.xyz) accept the request. Native
  Anthropic ignores the extra header.
- Remove `lg:sticky lg:top-20` from listing detail contact card — sidebar
  now scrolls with the page.
- Fix missing Vietnamese diacritics on AI estimate button:
  "Dinh gia AI" -> "Định giá AI", "Dang dinh gia..." -> "Đang định giá...".
  Tests updated accordingly.

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

apps/api/src/modules/analytics/application/queries/get-listing-ai-advice/get-listing-ai-advice.handler.ts

@@ -207,7 +207,11 @@ export class GetListingAiAdviceHandler
         method: 'POST',
         headers: {
           'Content-Type': 'application/json',
+          // Support both native Anthropic (x-api-key) and proxy-style gateways
+          // that expect Bearer auth (e.g. chat.trollllm.xyz). Anthropic ignores
+          // unknown headers, so sending both is safe.
           'x-api-key': args.apiKey,
+          Authorization: `Bearer ${args.apiKey}`,
           'anthropic-version': '2023-06-01',
           'anthropic-beta': 'prompt-caching-2024-07-31',
         },