fix(stability): optimize Go memory tiers, prevent nftables degradation deadlock, harden NTP & process supervision

- singbox/runtime.uc: add dynamic 4-tier GOMEMLIMIT and GOGC limits based on RAM, enforce /etc/tachyon/mem_scale, and install managed init script across all binary variants
- service/event_controller.uc: guard probe_nftables() with recovery_bypass and native_internet_restored checks to prevent 5-minute network drop deadlock
- service/watchdog.uc: reduce Telegram worker heartbeat timeout from 900s to 300s and add nslookup fallback to Zero-RTT prefetcher
- diagnostics/runtime.uc & service/lifecycle.uc: use direct-IP NTP pool to eliminate circular DNS/TLS deadlocks, and step clock forward on cold boot if RTC desynced
- service/failover.uc & diagnostics/runtime.uc: flush conntrack states on proxy group switch so client connections immediately migrate

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

@@ -642,6 +642,8 @@ function controller(bus, opts) {
 
     // ── Probe: nftables table and QoS marks ───────────────────────────────────
     function probe_nftables() {
+        if (setting("recovery_bypass", "0") == "1") return;
+        if (fs.stat("/var/run/tachyon/native_internet_restored") != null) return;
         if (is_list_update_running()) return;
         if (is_reload_in_progress()) return;
 
@@ -666,6 +668,7 @@ function controller(bus, opts) {
     // ── Probe: TPROXY port liveness ───────────────────────────────────────────
     function probe_tproxy() {
         if (setting("recovery_bypass", "0") == "1") return;
+        if (fs.stat("/var/run/tachyon/native_internet_restored") != null) return;
         if (is_reload_in_progress()) return;
 
         let pid = get_sing_box_pid();

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

@@ -121,6 +121,7 @@ function switch_group(section_name, outbound_name) {
         log_message("runtime switch failed: " + out, "warn");
         return false;
     }
+    command_status("conntrack -F >/dev/null 2>&1 || true");
     return true;
 }
 

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

@@ -835,6 +835,11 @@ function start_impl() {
     if (wd_status != 0)
         log_message("Watchdog start-runtime failed (status " + as_string(wd_status) + ")", "warn");
 
+    if (time() < 1704067200) {
+        log_message("System clock is in the past (RTC desync); performing quick NTP synchronization...", "warn");
+        command_status("ntpd -q -p 194.190.168.1 -p 216.239.35.0 -p 162.159.200.1 >/dev/null 2>&1 || true");
+    }
+
     let status = start_main();
     if (status != 0)
         return status;

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

@@ -349,7 +349,7 @@ function run_zero_rtt_prefetching() {
             // that followed it attached to a null command in this shell instead
             // of to the backgrounded loop. Backgrounding is now the wrapper's
             // job, so the loop gets the redirections it was always meant to have.
-            let batch_cmd = "for d in " + join(" ", batch) + "; do dig @127.0.0.1 \"$d\" A >/dev/null 2>&1; done";
+            let batch_cmd = "for d in " + join(" ", batch) + "; do dig @127.0.0.1 \"$d\" A >/dev/null 2>&1 || nslookup \"$d\" 127.0.0.1 >/dev/null 2>&1; done";
             system(common.background_command(batch_cmd));
             batch = [];
         }
@@ -1976,7 +1976,7 @@ function check_telegram_worker() {
     }
 
     let age = time() - int(heartbeat);
-    if (age <= 900)
+    if (age <= 300)
         return;
 
     let pid = trim(fs.readfile(TELEGRAM_PID_FILE) || "");