fix(tests): drop detect timeout-stub sleep from 5s to 2s

The "op hangs past timeoutMs" test was intermittently hitting vitest's
5000ms default testTimeout on CI. `_spawn.ts` waits for `child.on("close")`,
which only fires once the grandchild sleep exits — SIGKILL on the shell
wrapper doesn't cascade, so `sleep 5` kept the pipes open the full 5s.
Matches the keychain test's pattern (sleep 2 + timeoutMs: 100).

Local full run: 239/240 still green.

Author: yerzhansa

tests/secrets/backends/detect.test.ts

@@ -105,7 +105,10 @@ exit 2
   });
 
   it("returns unavailable/other with detail 'timeout' when op hangs past timeoutMs", async () => {
-    const opPath = await makeOpStub(`sleep 5`);
+    // sleep 2 (not 5) — _spawn.ts waits for `close` which only fires once the
+    // sleep child exits; under vitest's 5s default testTimeout, `sleep 5` is
+    // right on the edge and CI's Linux scheduler pushes it over.
+    const opPath = await makeOpStub(`sleep 2`);
     const result = await _detectBackendsWithOverrides({
       opPath,
       platform: "darwin",