fix(singbox): preserve cache.db across restarts and ensure parent directory

tachyon/files/usr/lib/service/lifecycle.uc

@@ -923,9 +923,6 @@ function stop_main() {
     if (module_success(NFT_UC, [ "tproxy-route6-present", RT_TABLE_NAME ]))
         command_success_from_args([ "ip", "-6", "route", "flush", "table", RT_TABLE_NAME ]);
 
-    let cache_path = uci_core.get(CONFIG_NAME + ".settings.cache_path") || "/tmp/sing-box/cache.db";
-    remove_file(cache_path);
-
     let sing_box_status = command_status_from_args([ "/etc/init.d/sing-box", "stop" ]);
     command_success_from_args([ "killall", "-q", "-9", "sing-box" ]);
     if (sing_box_status != 0)

tachyon/files/usr/lib/service/watchdog.uc

@@ -773,10 +773,9 @@ function heal_proxy_connectivity(ev) {
     let incident = {
         type: "proxy",
         description: "Зависание или неполный отклик прокси-порту sing-box (" + proxy_addr + ")",
-        resolution: "Очищена база cache.db и выполнен перезапуск sing-box"
+        resolution: "Выполнен перезапуск sing-box"
     };
 
-    remove_file("/tmp/sing-box/cache.db");
     // Reporting used to happen here, before the restart, so a rate-limited
     // attempt still announced a repair that never ran.
     if (!safe_proxy_restart("proxy_connectivity")) {

tachyon/files/usr/lib/singbox/generator.uc

@@ -394,6 +394,10 @@ function base_config(settings, service_address, runtime_context) {
     let rewrite_ttl = int_option(settings, "dns_rewrite_ttl", "60");
     let turbo_cache = bool_option(settings, "dns_turbo_cache", false);
     let cache_path = option(settings, "cache_path", turbo_cache ? "/etc/sing-box/cache.db" : "/tmp/sing-box/cache.db");
+    let cache_dir = replace(cache_path, /\/[^\/]+$/, "");
+    if (cache_dir != "" && cache_dir != cache_path) {
+        try { fs.mkdir(cache_dir, 0755); } catch(e) {}
+    }
     let dns_config = runtime_dns.config(settings);
     if (dns_config.unsupported)
         runtime_generate_unsupported(dns_config.unsupported);