feat: add supervisor prototype with embedded frontend

internal/domain/event.go

@@ -0,0 +1,32 @@
+package domain
+
+import "time"
+
+type EventType string
+
+const (
+	EventTerminalOutput EventType = "terminal.output"
+	EventSessionStatus  EventType = "session.status"
+	EventError          EventType = "error"
+)
+
+type Event struct {
+	Type      EventType       `json:"type"`
+	SessionID string          `json:"session"`
+	Payload   any             `json:"payload"`
+	At        time.Time       `json:"at"`
+}
+
+// TerminalOutputEvent carries raw terminal bytes as UTF-8 text.
+type TerminalOutputEvent struct {
+	Data string `json:"data"`
+}
+
+type SessionStatusEvent struct {
+	Status   SessionStatus `json:"status"`
+	ExitCode *int          `json:"exitCode,omitempty"`
+}
+
+type ErrorEvent struct {
+	Message string `json:"message"`
+}