fix: tighten shared chat envelope coverage

src/shared/chat-envelope.test.ts

@@ -14,6 +14,7 @@ describe("shared/chat-envelope", () => {
     expect(stripEnvelope("hello")).toBe("hello");
     expect(stripEnvelope("[note] hello")).toBe("[note] hello");
     expect(stripEnvelope("[2026/01/24 13:36] hello")).toBe("[2026/01/24 13:36] hello");
+    expect(stripEnvelope("[Teams] hello")).toBe("[Teams] hello");
   });
 
   it("removes standalone message id hint lines but keeps inline mentions", () => {
@@ -21,6 +22,7 @@ describe("shared/chat-envelope", () => {
     expect(stripMessageIdHints("hello\n [message_id: abc123] \nworld")).toBe("hello\nworld");
     expect(stripMessageIdHints("[message_id: abc123]\nhello")).toBe("hello");
     expect(stripMessageIdHints("[message_id: abc123]")).toBe("");
+    expect(stripMessageIdHints("hello\r\n[MESSAGE_ID: abc123]\r\nworld")).toBe("hello\nworld");
     expect(stripMessageIdHints("I typed [message_id: abc123] inline")).toBe(
       "I typed [message_id: abc123] inline",
     );

src/shared/chat-envelope.ts

@@ -39,7 +39,7 @@ export function stripEnvelope(text: string): string {
 }
 
 export function stripMessageIdHints(text: string): string {
-  if (!text.includes("[message_id:")) {
+  if (!/\[message_id:/i.test(text)) {
     return text;
   }
   const lines = text.split(/\r?\n/);