fix(bot): install libgssapi-krb5-2 in runtime image

Telegram bot's long-polling hangs after the first GetUpdates request
because libgssapi-krb5.so.2 is missing from the runtime-deps:10.0-noble
final image. .NET runtime attempts dlopen() of libgssapi during the
HTTPS handshake; without the library the HttpClient connection pool
enters an unrecoverable state and TelegramBotService never receives
new updates, even though SessionSchedulerService keeps sending
outgoing messages successfully.

Symptom (Loki, container gmrelaybot-bot-1):
  Telegram bot polling started
  Polling error, retrying in 5s
  Telegram.Bot.Exceptions.RequestException: Bot API Service Failure
  Cannot load library libgssapi_krb5.so.2

After the single Polling error, no Error handling update, no further
Polling error, and getUpdates from outside returns [] forever.

Fix: install libgssapi-krb5-2 alongside wget in the final stage of
src/GmRelay.Bot/Dockerfile. This also future-proofs Npgsql GSS/SSPI
Kerberos authentication for PostgreSQL.

Closes #129.

Bump version 3.9.5 -> 3.9.6

src/GmRelay.Bot/Dockerfile

@@ -30,8 +30,10 @@ RUN dotnet publish "GmRelay.Bot.csproj" -c Release -a $TARGETARCH -o /app/publis
 FROM mcr.microsoft.com/dotnet/runtime-deps:10.0-noble AS final
 WORKDIR /app
 
-# Устанавливаем wget для healthcheck
-RUN apt-get update && apt-get install -y --no-install-recommends wget \
+# Устанавливаем wget для healthcheck и libgssapi-krb5-2 для Npgsql GSS/SSPI
+# и HTTPS-handshake Telegram.Bot (без неё long-polling падает на первом запросе).
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    wget libgssapi-krb5-2 \
     && rm -rf /var/lib/apt/lists/*
 
 # Копируем только AOT-результаты из билда