Add module identity and outcome primitives

identity.go

@@ -0,0 +1,37 @@
+package commandkit
+
+import (
+	"context"
+	"io"
+)
+
+// Identity describes the application or component represented by CommandKit.
+//
+// Version and Revision are caller supplied metadata. CommandKit does not infer
+// them from an executable or mutate them.
+type Identity struct {
+	// Name is the human-readable application or component name.
+	Name string
+	// Version is the caller-supplied version string.
+	Version string
+	// Revision is the caller-supplied source revision.
+	Revision string
+}
+
+// Streams contains the output destinations associated with a command
+// invocation.
+type Streams struct {
+	// Out receives help and command reports.
+	Out io.Writer
+	// Err receives diagnostics and usage guidance.
+	Err io.Writer
+}
+
+// Invocation provides execution context and output streams to a command
+// handler.
+type Invocation struct {
+	// Context carries caller cancellation and request-scoped values.
+	Context context.Context
+	// Streams are the caller-selected output destinations.
+	Streams Streams
+}