Extend browser admin lifecycle actions

Support browser reboot and HTTPS stop through deferred control, plus
exact
`web certificate rotate --force` handoff to the dispatcher. Add typed
request
validation and focused boundary and lifecycle coverage.

tests/web_cookie_auth/run.py

@@ -43,6 +43,7 @@ esp_err_t httpd_ws_respond_server_handshake(httpd_req_t *, const char *);
 
 admin = "--admin" in sys.argv
 if admin:
+    HEADERS["esp_system.h"] = "#pragma once\nvoid esp_restart(void);\n"
     HEADERS["esp_heap_caps.h"] = """#pragma once
 #include <stddef.h>
 #define MALLOC_CAP_SPIRAM 1