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/agent/tools/search/firecrawl.go

@@ -22,12 +22,23 @@ import (
 	"io"
 	"net/http"
 	"net/url"
+	"time"
 
 	"go.gearno.de/kit/httpclient"
 	"go.probo.inc/probo/pkg/agent"
 )
 
 type (
+	searchResult struct {
+		Title   string `json:"title"`
+		URL     string `json:"url"`
+		Snippet string `json:"snippet"`
+	}
+
+	userAgentTransport struct {
+		next http.RoundTripper
+	}
+
 	firecrawlParams struct {
 		Query      string `json:"query" jsonschema:"The search query to execute"`
 		MaxResults int    `json:"max_results" jsonschema:"Maximum number of results to return (default 5, max 10)"`
@@ -52,11 +63,19 @@ type (
 	}
 )
 
+func (t *userAgentTransport) RoundTrip(r *http.Request) (*http.Response, error) {
+	r2 := r.Clone(r.Context())
+	r2.Header.Set("User-Agent", "Probo-Agent/1.0")
+	return t.next.RoundTrip(r2)
+}
+
 // FirecrawlSearchTool creates a tool that searches the web using the Firecrawl
 // API. The endpoint should be the base URL of the Firecrawl instance (e.g.
 // "https://api.firecrawl.dev/v2"). The apiKey is used for Bearer authentication.
 func FirecrawlSearchTool(endpoint, apiKey string) agent.Tool {
 	client := httpclient.DefaultPooledClient()
+	client.Timeout = 15 * time.Second
+	client.Transport = &userAgentTransport{next: client.Transport}
 
 	return agent.FunctionTool(
 		"web_search",