Handle exec shutdown on Interrupt (fixes immortal codex exec with websockets) (#10519)

### Motivation
- Ensure `codex exec` exits when a running turn is interrupted (e.g.,
Ctrl-C) so the CLI is not "immortal" when websockets/streaming are used.

### Description
- Return `CodexStatus::InitiateShutdown` when handling
`EventMsg::TurnAborted` in
`exec/src/event_processor_with_human_output.rs` so human-output exec
mode shuts down after an interrupt.
- Treat `protocol::EventMsg::TurnAborted` as
`CodexStatus::InitiateShutdown` in
`exec/src/event_processor_with_jsonl_output.rs` so JSONL output mode
behaves the same.
- Applied formatting with `just fmt`.

### Testing
- Ran `just fmt` successfully.
- Ran `cargo test -p codex-exec`; many unit tests ran and the test
command completed, but the full test run in this environment produced
`35 passed, 11 failed` where the failures are due to Landlock sandbox
panics and 403 responses in the test harness (environmental/integration
issues) and are not caused by the interrupt/shutdown changes.

------
[Codex
Task](https://chatgpt.com/codex/tasks/task_i_698165cec4e083258d17702bd29014c1)

codex-rs/exec/src/event_processor_with_human_output.rs

@@ -593,17 +593,20 @@ impl EventProcessor for EventProcessorWithHumanOutput {
                     view.path.display()
                 );
             }
-            EventMsg::TurnAborted(abort_reason) => match abort_reason.reason {
-                TurnAbortReason::Interrupted => {
-                    ts_msg!(self, "task interrupted");
+            EventMsg::TurnAborted(abort_reason) => {
+                match abort_reason.reason {
+                    TurnAbortReason::Interrupted => {
+                        ts_msg!(self, "task interrupted");
+                    }
+                    TurnAbortReason::Replaced => {
+                        ts_msg!(self, "task aborted: replaced by a new task");
+                    }
+                    TurnAbortReason::ReviewEnded => {
+                        ts_msg!(self, "task aborted: review ended");
+                    }
                 }
-                TurnAbortReason::Replaced => {
-                    ts_msg!(self, "task aborted: replaced by a new task");
-                }
-                TurnAbortReason::ReviewEnded => {
-                    ts_msg!(self, "task aborted: review ended");
-                }
-            },
+                return CodexStatus::InitiateShutdown;
+            }
             EventMsg::ContextCompacted(_) => {
                 ts_msg!(self, "context compacted");
             }

codex-rs/exec/src/event_processor_with_jsonl_output.rs

@@ -871,6 +871,7 @@ impl EventProcessor for EventProcessorWithJsonOutput {
                 }
                 CodexStatus::InitiateShutdown
             }
+            protocol::EventMsg::TurnAborted(_) => CodexStatus::InitiateShutdown,
             protocol::EventMsg::ShutdownComplete => CodexStatus::Shutdown,
             _ => CodexStatus::Running,
         }