fix(orchestrator): cap the hub at four CPUs

Piper TTS in the hub took every core of a host already at 94 to 100 % CPU. compose.yml now limits the hub to cpus: 4 next to its 2 GB memory limit, and TTS_TIMEOUT rises from 60 to 120 s so a line still renders under the cap. test_hub_speech pins both values.

🎯 Fix: 92 %
💥 Break: 3 %
💸 Cost: 100 %
⏱️ Time: 100 %
🛡️ Security: 100 %
🏆 Score: 89
🚦 Gate: ✅ 90/5, cost and time <= 100, security 100 %

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

orchestrator/compose.yml

@@ -15,6 +15,7 @@ services:
     security_opt:
       - no-new-privileges:true
     mem_limit: 2g
+    cpus: 4
     pids_limit: 256
     healthcheck:
       interval: 30s