Log execution outcomes (success / failure / timeout / launch error)

Hook runs were silently dropping their result into the void after
returning the HTTP response. For sync runs the body went to the
caller but nothing was logged; for async runs the result vanished
unless a callback was configured. That made debugging RunAs
failures (logon errors, missing executables) effectively
impossible since the service log only showed the 202.

Now every run emits one log line at INF (success) or WRN
(non-zero exit / timeout / launch error) with runId, slug, exit
code, duration, and truncated stdout/stderr.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/WebhookServer.Service/WebhookRouter.cs

@@ -126,6 +126,7 @@ public sealed class WebhookRouter
         }
 
         var result = await RunAsync(endpoint, ctx, http.RequestAborted).ConfigureAwait(false);
+        LogResult(endpoint, ctx, result);
         DispatchCallback(endpoint, ctx, result);
 
         if (result.LaunchError is not null)
@@ -157,6 +158,7 @@ public sealed class WebhookRouter
         try
         {
             var result = await RunAsync(endpoint, ctx, ct).ConfigureAwait(false);
+            LogResult(endpoint, ctx, result);
             DispatchCallback(endpoint, ctx, result);
         }
         catch (Exception ex)
@@ -165,6 +167,47 @@ public sealed class WebhookRouter
         }
     }
 
+    private void LogResult(EndpointConfig endpoint, ExecCtx ctx, ExecutionResult result)
+    {
+        if (result.LaunchError is not null)
+        {
+            _logger.LogWarning("Run {RunId} {Slug} failed to launch: {Error}",
+                ctx.RunId, ctx.Slug, result.LaunchError);
+            return;
+        }
+        if (result.TimedOut)
+        {
+            _logger.LogWarning("Run {RunId} {Slug} timed out after {Sec}s; process killed",
+                ctx.RunId, ctx.Slug, endpoint.TimeoutSeconds);
+            return;
+        }
+
+        var stdout = TruncateForLog(result.Stdout, 512);
+        var stderr = TruncateForLog(result.Stderr, 512);
+        if (result.Succeeded)
+        {
+            _logger.LogInformation(
+                "Run {RunId} {Slug} ok exit={Exit} dur={Ms}ms stdout={Stdout}{StderrPart}",
+                ctx.RunId, ctx.Slug, result.ExitCode, (long)result.Duration.TotalMilliseconds,
+                stdout, string.IsNullOrEmpty(stderr) ? "" : $" stderr={stderr}");
+        }
+        else
+        {
+            _logger.LogWarning(
+                "Run {RunId} {Slug} non-zero exit={Exit} dur={Ms}ms stdout={Stdout} stderr={Stderr}",
+                ctx.RunId, ctx.Slug, result.ExitCode, (long)result.Duration.TotalMilliseconds,
+                stdout, stderr);
+        }
+    }
+
+    private static string TruncateForLog(string s, int max)
+    {
+        if (string.IsNullOrEmpty(s)) return "(empty)";
+        var trimmed = s.Trim();
+        if (trimmed.Length <= max) return trimmed;
+        return trimmed.Substring(0, max) + $"... [+{trimmed.Length - max} chars]";
+    }
+
     private async Task<ExecutionResult> RunAsync(EndpointConfig endpoint, ExecCtx ctx, CancellationToken ct)
     {
         if (endpoint.Serialize)