Fix cooldown timer visibility after Start; add real-time modal validation; update context.md with prod server

- Cooldown counter now always rendered (hidden) when auto_reply active, shown dynamically via polling
- Modal form validates fields on blur/input with red highlight via .input-invalid class
- Telegram: switched back to tel.4mont.ru proxy (working via /etc/hosts on 192.168.33.19)
- context.md: added prod server 45.129.3.83, deploy commands, NPM routing notes

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app.py

@@ -1481,7 +1481,9 @@ def request_access():
         f"{geo_line}\n"
         f"🖥 <b>IP:</b> {ip}"
     )
-    _send_telegram(text)
+    ok = _send_telegram(text)
+    if not ok:
+        return jsonify({"ok": False, "error": "Не удалось отправить запрос. Попробуйте позже."}), 500
     return jsonify({"ok": True})