test(memory): give the #848 provenance test headroom on slow CI runners

Each GET /api/system/memory read costs ~600 ms on the shared ubuntu runner
(the route samples the live process), and the test performs eight reads —
5.2 s against bun's 5 s default timeout, which is how it flaked red on the
wp6 head while passing locally and on macos. Bump the per-test timeout to
20 s; the assertions and read count are unchanged.

Author: lidge-jun

tests/memory-watchdog.test.ts

@@ -296,7 +296,9 @@ describe("GET /api/system/memory", () => {
       else process.env.OCX_BUN_RUNTIME_SOURCE = inherited;
       delete process.env.OCX_BUN_RUNTIME_PATH;
     }
-  });
+    // The route costs ~600 ms per read on the shared CI runners, and this test makes
+    // eight of them — marginally over bun's 5 s default on a loaded box.
+  }, 20_000);
 
   test("GET system memory includes privacy-safe appOwnedBytes scalars", async () => {
     registerDefaultAppOwnedMemoryStores();