Remove UseHeadlessBrowser from JobProvider — all fetches now go via page-fetcher-api

page-fetcher-api always uses Playwright (networkidle by default), so the
per-provider flag that chose between headless and plain HTTP is obsolete.

- Removed from JobProviderEntity, CvSearchDbContext, JobProviderConfig, JobTokenService
- HtmlJobSearcher no longer passes WaitFor (uses page-fetcher-api default)
- EF migration drops the column from cvSearch.JobProviders

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Apis/cv-matcher-api/Services/JobTokenService.cs

@@ -128,7 +128,6 @@ public sealed class JobTokenService : IJobTokenService
             JobLinkContains = entity.JobLinkContains,
             InitialKeywords = keywords,
             MaxResults = entity.MaxResults,
-            UseHeadlessBrowser = entity.UseHeadlessBrowser,
             RequireKeywordInAnchor = entity.RequireKeywordInAnchor
         };
     }