- Introduce the oac-system-complete visual comm that fires on the
'systemComplete' trigger when a system's jumpgate research unlocks,
arming before the generic researchComplete sign-off so the FIFO plays
specific -> generic.
- Support an optional audioPool list of speech clips in CommsModel; the
hub picks one at random per arm so only the chosen clip is fetched and
cached, with validation that audio comms need a clip or pool.
- Wire GameScene to trigger systemComplete on activateGates when the
system nav chart is complete.
- Update comms tests for the new comm, pool normalization/asset rolling,
roster counts, and add a tether-rules audit script plus station shop
video references and lava assets.
