Node pager

Three fixes, all reported from the floor. ``` • Pages now reach every iPad right away. A room you page starts blinking, and the Finished button appears after a double-tap, without the occasional half-minute delay on one of the iPads • Room tiles always show the room's full name — no more names cut off with "…", and none at all once a room has been paged • Clear All now silences any pager tone or ding still playing, on every iPad, not just the one you pressed it on ``` **What changed underneath** (detail in sections 14-16 below): | | | |---|---| | **Late/missing pages** | A page was sent once and never repeated, so an iPad that missed it waited up to 30s for the next full sync — and staff presence, which the Finished button depends on, had no repeat at all. Added an adaptive re-sync and a timestamped presence sync. | | **Truncated room names** | The tile's controls claimed their width first, leaving the name almost nothing on a portrait iPad; a spacer then took half of what was left. The tile now sizes itself around the room name. | | **The remaining delay** | The alert sound was configuring the audio session synchronously on the main thread, in the middle of applying the update — the screen couldn't draw until it finished. All sound moved off the main thread. | | **Clear All** | Sounds were scheduled with no way to call them back. They're cancellable now, and Clear All tells the other iPads to go quiet too. |