fix(process): report no remaining time after a provider deadline fires

Node timers can fire while performance.now() is still a fraction of a
millisecond short of the monotonic deadline. ProviderStartupDeadline then
reported interruption "timeout" and an aborted signal while remainingMs()
returned ceil(0.x) = 1, so polling loops guarded by remainingMs() > 0
(Hopper and Ghidra startup) could run past an elapsed deadline, and the
real-timer test "aborts a bounded wait when its real monotonic deadline
expires" failed intermittently in CI (expected 1 to be 0).

Once the deadline's own timer has classified a timeout, report zero
remaining time. A deterministic regression test fires the timer with the
monotonic clock 0.4 ms short of the deadline.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/process/ProviderDeadline.test.ts

@@ -33,3 +33,20 @@ it("aborts a bounded wait when its real monotonic deadline expires", async () =>
     deadline.dispose();
   }
 });
+
+it("reports no remaining time once its timer fires before the monotonic deadline", () => {
+  vi.useFakeTimers({ toFake: ["setTimeout", "clearTimeout"] });
+  const now = vi.spyOn(performance, "now").mockReturnValue(1_000);
+  const deadline = new ProviderStartupDeadline(40);
+  try {
+    // Timers may fire while the monotonic clock is still just short of the deadline.
+    now.mockReturnValue(1_039.6);
+    vi.advanceTimersByTime(40);
+    expect(deadline.signal.aborted).toBe(true);
+    expect(deadline.interruption).toBe("timeout");
+    expect(deadline.remainingMs()).toBe(0);
+  } finally {
+    deadline.dispose();
+    vi.useRealTimers();
+  }
+});

src/process/ProviderDeadline.ts

@@ -85,6 +85,9 @@ export class ProviderStartupDeadline {
 
   /** Milliseconds still available to the next startup phase. */
   remainingMs(): number {
+    // Node timers can fire a fraction of a millisecond before the monotonic
+    // deadline, so an elapsed timer must not report time left to spend.
+    if (this.#interruption === "timeout") return 0;
     return Math.max(0, Math.ceil(this.#deadlineAt - performance.now()));
   }