fix(tmux-subagent): cap stale close retries

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/features/tmux-subagent/manager.ts

@@ -196,25 +196,30 @@ export class TmuxSessionManager {
         continue
       }
 
-      const nextRetryCount = tracked.closeRetryCount + 1
-      if (nextRetryCount >= MAX_CLOSE_RETRY_COUNT) {
-        log("[tmux-session-manager] force removing close-pending session after failed retry", {
-          sessionId: tracked.sessionId,
-          paneId: tracked.paneId,
-          closeRetryCount: nextRetryCount,
-        })
-        this.removeTrackedSession(tracked.sessionId)
+      const currentTracked = this.sessions.get(tracked.sessionId)
+      if (!currentTracked || !currentTracked.closePending) {
         continue
       }
 
-      this.sessions.set(tracked.sessionId, {
-        ...tracked,
+      const nextRetryCount = currentTracked.closeRetryCount + 1
+      if (nextRetryCount >= MAX_CLOSE_RETRY_COUNT) {
+        log("[tmux-session-manager] force removing close-pending session after failed retry", {
+          sessionId: currentTracked.sessionId,
+          paneId: currentTracked.paneId,
+          closeRetryCount: nextRetryCount,
+        })
+        this.removeTrackedSession(currentTracked.sessionId)
+        continue
+      }
+
+      this.sessions.set(currentTracked.sessionId, {
+        ...currentTracked,
         closePending: true,
         closeRetryCount: nextRetryCount,
       })
       log("[tmux-session-manager] retried close failed", {
-        sessionId: tracked.sessionId,
-        paneId: tracked.paneId,
+        sessionId: currentTracked.sessionId,
+        paneId: currentTracked.paneId,
         closeRetryCount: nextRetryCount,
       })
     }
@@ -642,6 +647,16 @@ export class TmuxSessionManager {
     const tracked = this.sessions.get(sessionId)
     if (!tracked) return
 
+    if (tracked.closePending && tracked.closeRetryCount >= MAX_CLOSE_RETRY_COUNT) {
+      log("[tmux-session-manager] force removing close-pending session after max retries", {
+        sessionId,
+        paneId: tracked.paneId,
+        closeRetryCount: tracked.closeRetryCount,
+      })
+      this.removeTrackedSession(sessionId)
+      return
+    }
+
     log("[tmux-session-manager] closing session pane", {
       sessionId,
       paneId: tracked.paneId,

src/features/tmux-subagent/zombie-pane.test.ts

@@ -134,6 +134,15 @@ function getRetryPendingCloses(target: object): () => Promise<void> {
   return retryPendingCloses.bind(target)
 }
 
+function getCloseSessionById(target: object): (sessionId: string) => Promise<void> {
+  const closeSessionById = Reflect.get(target, "closeSessionById")
+  if (typeof closeSessionById !== "function") {
+    throw new Error("Expected closeSessionById method")
+  }
+
+  return closeSessionById.bind(target)
+}
+
 function createManager(
   TmuxSessionManager: typeof import("./manager").TmuxSessionManager,
 ): import("./manager").TmuxSessionManager {
@@ -219,4 +228,44 @@ describe("TmuxSessionManager zombie pane handling", () => {
     expect(mockQueryWindowState).not.toHaveBeenCalled()
     expect(mockExecuteAction).not.toHaveBeenCalled()
   })
+
+  test("#given session with closePending true and closeRetryCount >= 3 #when closeSessionById called #then session is force-removed without retrying close", async () => {
+    // given
+    const { TmuxSessionManager } = await import("./manager")
+    const manager = createManager(TmuxSessionManager)
+    const sessions = getTrackedSessions(manager)
+    sessions.set(
+      "ses_pending",
+      createTrackedSession({ closePending: true, closeRetryCount: 3 }),
+    )
+
+    // when
+    await getCloseSessionById(manager)("ses_pending")
+
+    // then
+    expect(sessions.has("ses_pending")).toBe(false)
+    expect(mockQueryWindowState).not.toHaveBeenCalled()
+    expect(mockExecuteAction).not.toHaveBeenCalled()
+  })
+
+  test("#given close-pending session removed during async close #when retryPendingCloses fails #then it does not resurrect stale session state", async () => {
+    // given
+    const { TmuxSessionManager } = await import("./manager")
+    const manager = createManager(TmuxSessionManager)
+    const sessions = getTrackedSessions(manager)
+    sessions.set(
+      "ses_pending",
+      createTrackedSession({ closePending: true, closeRetryCount: 0 }),
+    )
+    mockExecuteAction.mockImplementationOnce(async () => {
+      sessions.delete("ses_pending")
+      return { success: false }
+    })
+
+    // when
+    await getRetryPendingCloses(manager)()
+
+    // then
+    expect(sessions.has("ses_pending")).toBe(false)
+  })
 })