Add recon form fingerprint library and SSRF canary mode.

Score crawl inputs by SSRF-prone field names and register ping-back canaries for operator paste confirmation.

server/internal/recon/parse.go

@@ -128,6 +128,7 @@ func parseURLFieldFromNamed(pageURL, name, id, placeholder string) *URLFieldFind
 			return &URLFieldFinding{
 				PageURL: pageURL,
 				Name:    label,
+				ID:      id,
 				Type:    "text",
 				Hint:    hint,
 			}