tests: dashboard tests wait for HITS and PROF before reading them

[JustVugg]

dev went red on the merge of #1819 in the "DeepSeek V4.1 tiny oracle" job, and green again on the next merge:

FAIL: test_brain_lights_up_and_shows_residents (tests.test_dsv41_dashboard...)
    self.assertEqual(len(experts["hits"]), ((bits + 7) // 8) * 2)
AssertionError: 0 != 12

#1819 only touched mimo.c and the family registry; the cause is a race in the test. The engine writes HITS and PROF after DONE. The gateway answers the HTTP request as soon as its dispatcher reads DONE, and the dispatcher reads the two lines after that, so a test that queries /experts right after the reply can see the grid before this turn's hits arrive. The qwen36 and glm53 dashboard tests read the endpoints the same way.

The endpoints already return a seq that counts the lines received. The three tests now wait until seq >= 1 on /experts and /profile (up to 30 s; past that they return what is there and the existing assertions name what is missing).

Checked

• With a local-only time.sleep(0.5) before the gateway records HITS, the test on dev fails exactly as on CI (0 != 12), and with this change it passes.
• Without the delay, both versions pass 5 out of 5 runs under full CPU load; the race needs the dispatcher to fall behind, which is why it shows up only now and then on CI.
• Tests only; the gateway and engines are unchanged.