Add browser deploy recon backend with port scan, web crawl, and deploy lane recommendations.

POST /api/v1/recon/scan probes fleet ports from the server host, crawls owned HTTP targets, maps findings to spread lanes, and records optional oath ledger rows.

server/internal/recon/hooks.go

@@ -0,0 +1,13 @@
+package recon
+
+import "time"
+
+// SetPortDialHook installs a test hook for TCP dials; pass nil to restore live dials.
+func SetPortDialHook(fn func(host string, port int, timeout time.Duration) bool) {
+	dialPortFn = fn
+}
+
+// SetFetchPageHook installs a test hook for HTTP fetches; pass nil to restore live GETs.
+func SetFetchPageHook(fn func(rawURL string) (status int, body string, err error)) {
+	fetchPageFn = fn
+}