fix(swift-package): Wait for real process exit after SIGTERM

Do not treat ChildProcess.killed as an exit signal when deciding whether\nto skip termination waits. The killed flag means a signal was sent,\nnot that the process has exited.\n\nUse exitCode/signalCode to detect actual exit, and keep bounded\nwait+SIGKILL behavior intact for stuck processes.\n\nAdd regression coverage that sets killed=true without an exit event\nand verifies we still escalate from SIGTERM to SIGKILL.

Co-Authored-By: OpenAI Codex <noreply@openai.com>

Author: cameroncooke

src/mcp/tools/swift-package/__tests__/active-processes.test.ts

@@ -10,6 +10,7 @@ import {
   addProcess,
   removeProcess,
   clearAllProcesses,
+  terminateTrackedProcess,
   type ProcessInfo,
 } from '../active-processes.ts';
 import {
@@ -213,6 +214,34 @@ describe('active-processes module', () => {
     });
   });
 
+  describe('process termination helper', () => {
+    it('does not treat killed=true as exited after SIGTERM', async () => {
+      const signals: string[] = [];
+
+      addProcess(4242, {
+        process: {
+          kill: (signal?: string) => {
+            signals.push(signal ?? 'SIGTERM');
+          },
+          on: () => {
+            // never emits exit; allow timeout path
+          },
+          killed: true,
+          exitCode: null,
+          signalCode: null,
+          pid: 4242,
+        },
+        startedAt: new Date('2023-01-01T00:00:00.000Z'),
+      });
+
+      const result = await terminateTrackedProcess(4242, 25);
+
+      expect(result.status).toBe('terminated');
+      expect(result.usedForceKill).toBe(true);
+      expect(signals).toEqual(['SIGTERM', 'SIGKILL']);
+    });
+  });
+
   describe('ProcessInfo interface', () => {
     it('should work with complete process object', () => {
       const mockProcess = {

src/mcp/tools/swift-package/active-processes.ts

@@ -11,6 +11,7 @@ interface TrackedProcess {
   removeListener?: (event: string, callback: () => void) => void;
   pid?: number;
   exitCode?: number | null;
+  signalCode?: string | null;
   killed?: boolean;
 }
 
@@ -64,7 +65,7 @@ async function terminateProcess(
     return { error: error instanceof Error ? error.message : String(error) };
   }
 
-  const alreadyExited = info.process.exitCode != null || info.process.killed === true;
+  const alreadyExited = info.process.exitCode != null || info.process.signalCode != null;
   if (alreadyExited) {
     return {};
   }