feat: add health check endpoints for Bot and Web

- Web: add /health endpoint with PostgreSQL readiness check (returns 200+JSON or 503)
- Web: add /alive endpoint for liveness probe
- Bot: add BotHealthCheckHostedService serving /health on port 8081 via HttpListener
- Bot: expose port 8081 in Dockerfile and install wget for healthcheck
- compose.yaml: add healthcheck sections for bot and web services
- tests: add TDD tests for both health endpoints

Bump version -> 1.16.0

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/GmRelay.Bot/Dockerfile

@@ -30,9 +30,15 @@ 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 \
+    && rm -rf /var/lib/apt/lists/*
+
 # Копируем только AOT-результаты из билда
 COPY --from=build /app/publish .
 
+EXPOSE 8081
+
 USER $APP_UID
 
 # Запуск скомпилированного AOT бинарного файла напрямую

src/GmRelay.Bot/Infrastructure/Health/BotHealthCheckHostedService.cs

@@ -0,0 +1,99 @@
+using System.Net;
+
+namespace GmRelay.Bot.Infrastructure.Health;
+
+public sealed class BotHealthCheckHostedService : IHostedService
+{
+    private readonly ILogger<BotHealthCheckHostedService> _logger;
+    private readonly string _prefix;
+    private HttpListener? _listener;
+    private CancellationTokenSource? _cts;
+    private Task? _listenerTask;
+
+    public BotHealthCheckHostedService(
+        ILogger<BotHealthCheckHostedService> logger,
+        IConfiguration configuration)
+    {
+        _logger = logger;
+        _prefix = configuration.GetValue("HealthCheck:Prefix", "http://+:8081/")!;
+    }
+
+    public Task StartAsync(CancellationToken cancellationToken)
+    {
+        _cts = new CancellationTokenSource();
+        _listener = new HttpListener();
+        _listener.Prefixes.Add(_prefix);
+        _listener.Start();
+
+        _logger.LogInformation("Health check server started on {Prefix}", _prefix);
+
+        _listenerTask = Task.Run(async () => await ListenAsync(_cts.Token), cancellationToken);
+
+        return Task.CompletedTask;
+    }
+
+    public async Task StopAsync(CancellationToken cancellationToken)
+    {
+        _cts?.Cancel();
+        _listener?.Stop();
+
+        if (_listenerTask != null)
+        {
+            await Task.WhenAny(_listenerTask, Task.Delay(TimeSpan.FromSeconds(5), cancellationToken));
+        }
+
+        _listener?.Close();
+        _logger.LogInformation("Health check server stopped");
+    }
+
+    private async Task ListenAsync(CancellationToken cancellationToken)
+    {
+        while (_listener?.IsListening == true && !cancellationToken.IsCancellationRequested)
+        {
+            try
+            {
+                var context = await _listener.GetContextAsync();
+                _ = Task.Run(() => HandleRequestAsync(context), cancellationToken);
+            }
+            catch (HttpListenerException) when (cancellationToken.IsCancellationRequested)
+            {
+                break;
+            }
+            catch (ObjectDisposedException)
+            {
+                break;
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Error in health check listener");
+            }
+        }
+    }
+
+    private async Task HandleRequestAsync(HttpListenerContext context)
+    {
+        try
+        {
+            var request = context.Request;
+            var response = context.Response;
+
+            if (request.Url?.AbsolutePath == "/health")
+            {
+                response.StatusCode = (int)HttpStatusCode.OK;
+                response.ContentType = "application/json";
+                var body = "{\"status\":\"healthy\"}"u8.ToArray();
+                await response.OutputStream.WriteAsync(body);
+            }
+            else
+            {
+                response.StatusCode = (int)HttpStatusCode.NotFound;
+            }
+
+            response.Close();
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "Error handling health check request");
+        }
+    }
+}

src/GmRelay.Bot/Program.cs

@@ -6,6 +6,7 @@ using GmRelay.Bot.Features.Reminders.SendOneHourReminder;
 using GmRelay.Bot.Features.Sessions.CreateSession;
 using GmRelay.Bot.Features.Sessions.RescheduleSession;
 using GmRelay.Bot.Infrastructure.Database;
+using GmRelay.Bot.Infrastructure.Health;
 using GmRelay.Bot.Infrastructure.Logging;
 using GmRelay.Bot.Infrastructure.Scheduling;
 using GmRelay.Bot.Infrastructure.Telegram;
@@ -85,6 +86,9 @@ builder.Services.AddSingleton<ISessionTriggerStore, DbSessionTriggerStore>();
 builder.Services.AddHostedService<SessionSchedulerService>();
 builder.Services.AddHostedService<RescheduleVotingDeadlineService>();
 
+// ── Health check server ──────────────────────────────────────────────
+builder.Services.AddHostedService<BotHealthCheckHostedService>();
+
 var host = builder.Build();
 
 // ── Run database migrations on startup ───────────────────────────────