fix: reject launchd pid sentinel values

Landed from contributor PR #39281 by @mvanhorn.

Co-authored-by: Matt Van Horn <mvanhorn@gmail.com>

src/daemon/launchd.test.ts

@@ -102,6 +102,26 @@ describe("launchd runtime parsing", () => {
       lastExitReason: "exited",
     });
   });
+
+  it("does not set pid when pid = 0", () => {
+    const output = ["state = running", "pid = 0"].join("\n");
+    const info = parseLaunchctlPrint(output);
+    expect(info.pid).toBeUndefined();
+    expect(info.state).toBe("running");
+  });
+
+  it("sets pid for positive values", () => {
+    const output = ["state = running", "pid = 1234"].join("\n");
+    const info = parseLaunchctlPrint(output);
+    expect(info.pid).toBe(1234);
+  });
+
+  it("does not set pid for negative values", () => {
+    const output = ["state = waiting", "pid = -1"].join("\n");
+    const info = parseLaunchctlPrint(output);
+    expect(info.pid).toBeUndefined();
+    expect(info.state).toBe("waiting");
+  });
 });
 
 describe("launchctl list detection", () => {

src/daemon/launchd.ts

@@ -128,7 +128,7 @@ export function parseLaunchctlPrint(output: string): LaunchctlPrintInfo {
   const pidValue = entries.pid;
   if (pidValue) {
     const pid = Number.parseInt(pidValue, 10);
-    if (Number.isFinite(pid)) {
+    if (Number.isFinite(pid) && pid > 0) {
       info.pid = pid;
     }
   }