Remove SearXNG search backend, use Firecrawl exclusively

SearXNG was a fallback search backend that added complexity without
being used in practice. All search-dependent features (web search,
government DB checks, vetting orchestrator, tracker mapping) now use
Firecrawl exclusively. Removes the SEARCH_ENDPOINT config plumbing
from probodconfig, bootstrap, Helm charts, and all callers.

Signed-off-by: Émile Ré <emile@probo.com>

pkg/cookiebanner/tracker_mapping_worker.go

@@ -53,7 +53,6 @@ type trackerMappingHandler struct {
 type TrackerMappingConfig struct {
 	LLMClient         *llm.Client
 	Model             string
-	SearchEndpoint    string
 	FirecrawlEndpoint string
 	FirecrawlAPIKey   string
 }
@@ -93,8 +92,6 @@ func buildTrackerMappingAgent(
 
 	if cfg.FirecrawlEndpoint != "" && cfg.FirecrawlAPIKey != "" {
 		tools = append(tools, search.FirecrawlSearchTool(cfg.FirecrawlEndpoint, cfg.FirecrawlAPIKey))
-	} else if cfg.SearchEndpoint != "" {
-		tools = append(tools, search.WebSearchTool(cfg.SearchEndpoint))
 	}
 
 	outputType, err := agent.NewOutputType[TrackerIdentification]("tracker_identification")