feat(logging): shared LoggingSetup with build-config sink branching

tests/ClaudeDo.Worker.Tests/Logging/LoggingSetupTests.cs

@@ -0,0 +1,30 @@
+using ClaudeDo.Logging;
+using Serilog;
+
+namespace ClaudeDo.Worker.Tests.Logging;
+
+public sealed class LoggingSetupTests
+{
+    [Fact]
+    public void Configure_WritesSharedLogFile()
+    {
+        var logRoot = Path.Combine(Path.GetTempPath(), "claudedo-logtest-" + Guid.NewGuid().ToString("N"));
+        Directory.CreateDirectory(logRoot);
+        try
+        {
+            var logger = LoggingSetup.Configure(new LoggerConfiguration(), "test", logRoot).CreateLogger();
+            logger.Warning("marker-{Marker}", "xyz");
+            logger.Dispose(); // flush + release the file handle
+
+            var files = Directory.GetFiles(logRoot, "claudedo-*.log");
+            var file = Assert.Single(files);
+            var contents = File.ReadAllText(file);
+            Assert.Contains("marker-", contents);
+            Assert.Contains("test/", contents); // {Process} tag in the template
+        }
+        finally
+        {
+            try { Directory.Delete(logRoot, recursive: true); } catch { /* best effort */ }
+        }
+    }
+}