e2e: M8 milestone check

scripts/e2e/m8-check.mjs, the scenario from 09 M8 with real calls from
a DID: queue 550 with agents 340 and 341, max wait 30 s, then 342. 340
pauses with *45550 and 341 is paused by an admin, so three callers
wait. 341 comes back and gets the longest waiting caller, parks them
on 701 (blind transfer to 700) and 343 picks up by dialing 701; 341
takes the next caller and the last one rings 342 after 30 s. Stats:
3 offered, 2 answered, 1 timed out.

Roadmap marks the M8 milestone check done; the e2e README describes
m8-t4, m8-t5 and m8-check.

Task: M8-check

docs/spec/09-roadmap.md

@@ -207,7 +207,7 @@ Legend: 📖 read · 🔨 build · ✅ done when
 **M8-T4** Paging/intercom (`sp-page-*`, `*80`) + auto-answer test on a real Yealink or Grandstream.
 As built: tested with baresip phones that honor the auto-answer headers (`sip_autoanswer`). **Open:** the check on a real Yealink or Grandstream, when one is available.
 **M8-T5** MOH classes (03 §8).
-✅ Golden `queue` case passes. Scenario: 3 callers wait in a queue with 2 agents. One agent pauses with `*45550`. The caller who waits past `max_wait_seconds` goes to the timeout destination. A parked call on 701 can be picked up from another phone.
+✅ **Milestone check:** golden `queue` case passes. Scenario: 3 callers wait in a queue with 2 agents. One agent pauses with `*45550`. The caller who waits past `max_wait_seconds` goes to the timeout destination. A parked call on 701 can be picked up from another phone. **Done as `scripts/e2e/m8-check.mjs` (callers from a DID; the agent who answers parks the call and another phone picks up 701).**
 
 ---