fix(imessage): normalize messaging targets (#1708)

Co-authored-by: Aaron Ng <1653630+aaronn@users.noreply.github.com>

src/channels/plugins/normalize/imessage.test.ts

@@ -0,0 +1,15 @@
+import { describe, expect, it } from "vitest";
+
+import { normalizeIMessageMessagingTarget } from "./imessage.js";
+
+describe("imessage target normalization", () => {
+  it("preserves service prefixes for handles", () => {
+    expect(normalizeIMessageMessagingTarget("sms:+1 (555) 222-3333")).toBe("sms:+15552223333");
+  });
+
+  it("drops service prefixes for chat targets", () => {
+    expect(normalizeIMessageMessagingTarget("sms:chat_id:123")).toBe("chat_id:123");
+    expect(normalizeIMessageMessagingTarget("imessage:CHAT_GUID:abc")).toBe("chat_guid:abc");
+    expect(normalizeIMessageMessagingTarget("auto:ChatIdentifier:foo")).toBe("chat_identifier:foo");
+  });
+});