Fix job search: location filtering, keyword quality, anchor filter bypass

Closes #41

- Add RequireKeywordInAnchor per-provider flag (default true); set false for
  ejobs.ro and bestjobs.eu so Stage 2 anchor-text filter is skipped — their
  search URL already filters by relevance server-side
- Update AI system prompts (en + ro) to extract concise job-board-friendly
  keywords (role title + key tech, not abstract concepts) and candidate location
- Propagate location through JobMatchResponse -> CreateJobSearchTokenRequest ->
  JobSearchTokenEntity -> JobSearchSessionEntity
- Add {location} and {location-slug} substitution in HtmlJobSearcher
- Update provider SearchUrlTemplates to include location:
    ejobs.ro:    /locuri-de-munca/{location-slug}?q={keywords}
    bestjobs.eu: /ro/locuri-de-munca-in-{location-slug}?keywords={keywords}
    linkedin.com: ?keywords={keywords}&location={location}
- Three new migrations: AddRequireKeywordInAnchorAndLocation,
  ImproveKeywordsAndAddLocation, AddLocationToProviders

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

Jobs/cv-search-job/Services/HtmlJobSearcher.cs

@@ -33,6 +33,7 @@ public sealed class HtmlJobSearcher
     public async Task<IReadOnlyList<string>> SearchJobUrlsAsync(
         JobProviderConfig provider,
         IReadOnlyList<string> cvKeywords,
+        string? location,
         CancellationToken ct)
     {
         var allKeywords = provider.InitialKeywords
@@ -48,13 +49,23 @@ public sealed class HtmlJobSearcher
         }
 
         var keywordsEncoded = HttpUtility.UrlEncode(string.Join(" ", allKeywords));
-        var searchUrl = provider.SearchUrlTemplate.Replace("{keywords}", keywordsEncoded);
+        var locationEncoded = HttpUtility.UrlEncode(location ?? string.Empty);
+        var locationSlug = (location ?? string.Empty)
+            .ToLowerInvariant()
+            .Replace(",", "")
+            .Replace(" ", "-")
+            .Trim('-');
+        var searchUrl = provider.SearchUrlTemplate
+            .Replace("{keywords}", keywordsEncoded)
+            .Replace("{location}", locationEncoded)
+            .Replace("{location-slug}", locationSlug);
 
         _logger.LogInformation(
-            "Provider {Provider}: fetching {Url} [{Mode}] | CV keywords: [{Keywords}]",
+            "Provider {Provider}: fetching {Url} [{Mode}] | CV keywords: [{Keywords}] | Location: {Location}",
             provider.Name, searchUrl,
             provider.UseHeadlessBrowser ? "headless" : "http",
-            string.Join(", ", cvKeywords));
+            string.Join(", ", cvKeywords),
+            location ?? "(none)");
 
         string? html;
         if (provider.UseHeadlessBrowser)
@@ -89,7 +100,8 @@ public sealed class HtmlJobSearcher
 
             stage1Pass++;
 
-            if (!cvKeywords.Any(k => anchorText.Contains(k, StringComparison.OrdinalIgnoreCase)))
+            if (provider.RequireKeywordInAnchor &&
+                !cvKeywords.Any(k => anchorText.Contains(k, StringComparison.OrdinalIgnoreCase)))
             {
                 _logger.LogDebug(
                     "Provider {Provider}: stage-2 reject | href={Href} | text={Text}",