feat(cli): cancel in-flight model requests on turn interruption

Wire the runtime's TurnInterruptSignal through the CLI turn lifecycle:

- AnthropicRuntimeClient races the streaming request against the
  interrupt flag with tokio::select!; when the flag trips, the request
  future is dropped, aborting the in-flight HTTP stream for every
  provider variant.
- BuiltRuntime installs the shared signal into both the conversation
  loop and the API client.
- The per-turn Ctrl+C monitor now interrupts the whole turn instead of
  only aborting running hooks, so Ctrl+C mid-turn returns to the REPL
  prompt with partial output instead of leaving the request running.
- The REPL spinner reports an interrupted turn distinctly from a
  completed one.

Part of the Esc-to-interrupt work (#3196); the Esc key listener lands
separately.

rust/crates/rusty-claude-cli/src/main.rs

@@ -7298,6 +7298,18 @@ impl BuiltRuntime {
         self
     }
 
+    fn with_turn_interrupt_signal(mut self, signal: runtime::TurnInterruptSignal) -> Self {
+        let mut runtime = self
+            .runtime
+            .take()
+            .expect("runtime should exist before installing turn interrupt signal");
+        runtime
+            .api_client_mut()
+            .set_turn_interrupt_signal(signal.clone());
+        self.runtime = Some(runtime.with_turn_interrupt_signal(signal));
+        self
+    }
+
     fn shutdown_plugins(&mut self) -> Result<(), Box<dyn std::error::Error>> {
         if self.plugins_active {
             self.plugin_registry.shutdown()?;
@@ -7680,7 +7692,10 @@ struct HookAbortMonitor {
 }
 
 impl HookAbortMonitor {
-    fn spawn(abort_signal: runtime::HookAbortSignal) -> Self {
+    fn spawn(
+        abort_signal: runtime::HookAbortSignal,
+        turn_interrupt_signal: runtime::TurnInterruptSignal,
+    ) -> Self {
         Self::spawn_with_waiter(abort_signal, move |stop_rx, abort_signal| {
             let Ok(runtime) = tokio::runtime::Builder::new_current_thread()
                 .enable_all()
@@ -7697,7 +7712,11 @@ impl HookAbortMonitor {
                 tokio::select! {
                     result = tokio::signal::ctrl_c() => {
                         if result.is_ok() {
+                            // Ctrl+C stops the whole turn, not just running
+                            // hooks: the conversation loop and the streaming
+                            // client both poll the turn interrupt signal.
                             abort_signal.abort();
+                            turn_interrupt_signal.interrupt();
                         }
                     }
                     _ = wait_for_stop => {}
@@ -7831,6 +7850,7 @@ impl LiveCli {
         terminal_tail: TerminalTail,
     ) -> Result<(BuiltRuntime, HookAbortMonitor), Box<dyn std::error::Error>> {
         let hook_abort_signal = runtime::HookAbortSignal::new();
+        let turn_interrupt_signal = runtime::TurnInterruptSignal::new();
         let runtime = build_runtime(
             self.runtime.session().clone(),
             &self.session.id,
@@ -7843,8 +7863,9 @@ impl LiveCli {
             self.permission_mode,
             None,
         )?
-        .with_hook_abort_signal(hook_abort_signal.clone());
-        let hook_abort_monitor = HookAbortMonitor::spawn(hook_abort_signal);
+        .with_hook_abort_signal(hook_abort_signal.clone())
+        .with_turn_interrupt_signal(turn_interrupt_signal.clone());
+        let hook_abort_monitor = HookAbortMonitor::spawn(hook_abort_signal, turn_interrupt_signal);
 
         Ok((runtime, hook_abort_monitor))
     }
@@ -7892,7 +7913,11 @@ impl LiveCli {
                     println!();
                 }
                 spinner.finish(
-                    "✨ Done",
+                    if summary.interrupted {
+                        "⏹ Interrupted"
+                    } else {
+                        "✨ Done"
+                    },
                     TerminalRenderer::new().color_theme(),
                     &mut stdout,
                 )?;
@@ -12984,6 +13009,7 @@ struct AnthropicRuntimeClient {
     tool_registry: GlobalToolRegistry,
     progress_reporter: Option<InternalPromptProgressReporter>,
     reasoning_effort: Option<String>,
+    turn_interrupt_signal: Option<runtime::TurnInterruptSignal>,
 }
 
 impl AnthropicRuntimeClient {
@@ -13069,12 +13095,17 @@ impl AnthropicRuntimeClient {
             tool_registry,
             progress_reporter,
             reasoning_effort: None,
+            turn_interrupt_signal: None,
         })
     }
 
     fn set_reasoning_effort(&mut self, effort: Option<String>) {
         self.reasoning_effort = effort;
     }
+
+    fn set_turn_interrupt_signal(&mut self, signal: runtime::TurnInterruptSignal) {
+        self.turn_interrupt_signal = Some(signal);
+    }
 }
 
 fn resolve_cli_auth_source() -> Result<AuthSource, Box<dyn std::error::Error>> {
@@ -13118,30 +13149,50 @@ impl ApiClient for AnthropicRuntimeClient {
         };
 
         self.runtime.block_on(async {
-            // When resuming after tool execution, apply a stall timeout on the
-            // first stream event.  If the model does not respond within the
-            // deadline we drop the stalled connection and re-send the request as
-            // a continuation nudge (one retry only).
-            let max_attempts: usize = if is_post_tool { 2 } else { 1 };
+            let request_loop = async {
+                // When resuming after tool execution, apply a stall timeout on the
+                // first stream event.  If the model does not respond within the
+                // deadline we drop the stalled connection and re-send the request as
+                // a continuation nudge (one retry only).
+                let max_attempts: usize = if is_post_tool { 2 } else { 1 };
 
-            for attempt in 1..=max_attempts {
-                let result = self
-                    .consume_stream(&message_request, is_post_tool && attempt == 1)
-                    .await;
-                match result {
-                    Ok(events) => return Ok(events),
-                    Err(error)
-                        if error.to_string().contains("post-tool stall")
-                            && attempt < max_attempts =>
-                    {
-                        // Stalled after tool completion — nudge the model by
-                        // re-sending the same request.
+                for attempt in 1..=max_attempts {
+                    let result = self
+                        .consume_stream(&message_request, is_post_tool && attempt == 1)
+                        .await;
+                    match result {
+                        Ok(events) => return Ok(events),
+                        Err(error)
+                            if error.to_string().contains("post-tool stall")
+                                && attempt < max_attempts =>
+                        {
+                            // Stalled after tool completion — nudge the model by
+                            // re-sending the same request.
+                        }
+                        Err(error) => return Err(error),
                     }
-                    Err(error) => return Err(error),
+                }
+
+                Err(RuntimeError::new("post-tool continuation nudge exhausted"))
+            };
+
+            let Some(interrupt) = self.turn_interrupt_signal.clone() else {
+                return request_loop.await;
+            };
+
+            tokio::select! {
+                result = request_loop => result,
+                () = async {
+                    while !interrupt.is_interrupted() {
+                        tokio::time::sleep(std::time::Duration::from_millis(50)).await;
+                    }
+                } => {
+                    // Dropping the request future aborts the in-flight HTTP
+                    // stream. The conversation loop sees the interrupt flag and
+                    // reports this as an interruption rather than a failure.
+                    Err(RuntimeError::new("request interrupted by user"))
                 }
             }
-
-            Err(RuntimeError::new("post-tool continuation nudge exhausted"))
         })
     }
 }