fix(copilot): mark internal background notifications as agent-initiated

src/shared/index.ts

@@ -57,3 +57,4 @@ export * from "./opencode-message-dir"
 export * from "./normalize-sdk-response"
 export * from "./session-directory-resolver"
 export * from "./prompt-tools"
+export * from "./internal-initiator-marker"

src/shared/internal-initiator-marker.ts

@@ -0,0 +1,13 @@
+export const OMO_INTERNAL_INITIATOR_MARKER = "<!-- OMO_INTERNAL_INITIATOR -->"
+
+export function createInternalAgentTextPart(text: string): {
+  type: "text"
+  text: string
+  synthetic: true
+} {
+  return {
+    type: "text",
+    text: `${text}\n${OMO_INTERNAL_INITIATOR_MARKER}`,
+    synthetic: true,
+  }
+}