Stop phantom-notification hangs and drop noisy "0초" progress label

Agents ended turns with "I'll wait … I'll be notified" expecting a
background-completion callback that this environment never delivers, so
the turn hung and left the planning sentence stuck in the channel. Add a
claude-platform rule that no such notification exists — finish within the
turn (foreground/poll) or ask the user for a follow-up.

Also suppress the elapsed-time suffix on progress messages until at least
one 5s bucket has elapsed, so freshly-created progress no longer shows a
meaningless "0초". Update the affected message-runtime expectations.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/message-runtime.test.ts

@@ -4172,7 +4172,7 @@ describe('createMessageRuntime', () => {
       // First progress flushed when the second progress arrives
       expect(channel.sendAndTrack).toHaveBeenCalledWith(
         chatJid,
-        P('CI 상태 확인 중입니다.\n\n0초'),
+        P('CI 상태 확인 중입니다.'),
       );
       // Timer tick edits the tracked progress with updated elapsed time
       expect(channel.editMessage).toHaveBeenCalledWith(
@@ -4272,11 +4272,11 @@ describe('createMessageRuntime', () => {
     // First progress flushed when second arrives — sendAndTrack throws, falls back to sendMessage
     expect(channel.sendAndTrack).toHaveBeenCalledWith(
       chatJid,
-      P('진행 중입니다.\n\n0초'),
+      P('진행 중입니다.'),
     );
     expect(channel.sendMessage).toHaveBeenCalledWith(
       chatJid,
-      P('진행 중입니다.\n\n0초'),
+      P('진행 중입니다.'),
     );
   });
 
@@ -4353,11 +4353,11 @@ describe('createMessageRuntime', () => {
     // First progress flushed when second arrives — sendAndTrack returns null, falls back to sendMessage
     expect(channel.sendAndTrack).toHaveBeenCalledWith(
       chatJid,
-      P('진행 중입니다.\n\n0초'),
+      P('진행 중입니다.'),
     );
     expect(channel.sendMessage).toHaveBeenCalledWith(
       chatJid,
-      P('진행 중입니다.\n\n0초'),
+      P('진행 중입니다.'),
     );
   });
 
@@ -4461,7 +4461,7 @@ describe('createMessageRuntime', () => {
       expect(channel.sendAndTrack).toHaveBeenCalledTimes(1);
       expect(channel.sendAndTrack).toHaveBeenCalledWith(
         chatJid,
-        P('첫 번째 진행상황입니다.\n\n0초'),
+        P('첫 번째 진행상황입니다.'),
       );
       // Timer tick updates tracked progress via edit
       expect(channel.editMessage).toHaveBeenCalledWith(
@@ -4573,7 +4573,7 @@ describe('createMessageRuntime', () => {
       // First progress flushed when second arrives
       expect(channel.sendAndTrack).toHaveBeenCalledWith(
         chatJid,
-        P('오래 걸리는 작업입니다.\n\n0초'),
+        P('오래 걸리는 작업입니다.'),
       );
       // Timer ticks update the tracked progress with longer durations
       expect(channel.editMessage).toHaveBeenCalledWith(
@@ -4679,7 +4679,7 @@ describe('createMessageRuntime', () => {
       // First progress flushed when second arrives
       expect(channel.sendAndTrack).toHaveBeenCalledWith(
         chatJid,
-        P('테스트를 돌리는 중입니다.\n\n0초'),
+        P('테스트를 돌리는 중입니다.'),
       );
       // Timer tick updates tracked progress
       expect(channel.editMessage).toHaveBeenCalledWith(
@@ -5088,13 +5088,13 @@ describe('createMessageRuntime', () => {
       expect(channel.sendAndTrack).toHaveBeenNthCalledWith(
         1,
         chatJid,
-        P('첫 번째 진행상황입니다.\n\n0초'),
+        P('첫 번째 진행상황입니다.'),
       );
       // After empty final resets state, third progress flushed when fourth arrives (new message)
       expect(channel.sendAndTrack).toHaveBeenNthCalledWith(
         2,
         chatJid,
-        P('두 번째 진행상황입니다.\n\n0초'),
+        P('두 번째 진행상황입니다.'),
       );
       // Timer tick edits the first tracked progress
       expect(channel.editMessage).toHaveBeenCalledWith(
@@ -5213,7 +5213,7 @@ describe('createMessageRuntime', () => {
       // First progress flushed when second arrives
       expect(channel.sendAndTrack).toHaveBeenCalledWith(
         chatJid,
-        P('검증 중입니다.\n\n0초'),
+        P('검증 중입니다.'),
       );
       // Once the tracked progress exists, later progress updates replace the visible heading directly.
       expect(channel.editMessage).toHaveBeenCalledWith(
@@ -5329,7 +5329,7 @@ describe('createMessageRuntime', () => {
       // The first flushed progress is still tracked
       expect(channel.sendAndTrack).toHaveBeenCalledWith(
         chatJid,
-        P('진행 중입니다.\n\n0초'),
+        P('진행 중입니다.'),
       );
       // Edit is attempted on the tracked message (first fails, subsequent succeed)
       expect(channel.editMessage).toHaveBeenCalledWith(
@@ -5568,7 +5568,7 @@ describe('createMessageRuntime', () => {
     // First progress flushed when second arrives
     expect(channel.sendAndTrack).toHaveBeenCalledWith(
       chatJid,
-      P('중간 진행상황입니다.\n\n0초'),
+      P('중간 진행상황입니다.'),
     );
     // Error replaces the tracked progress message with the failure final
     expect(channel.sendMessage).not.toHaveBeenCalled();