Design multi-tab-safe collection reset coordination for web

[kilbot]

Summary

Track the follow-up work to make RxDB collection reset operations safe and predictable across multiple open POS tabs/windows.

Why

As part of the RxDB 17 / storage migration work, web will move to OPFS for performance. That migration is intentionally scoped to storage/platform changes only.

However, collection lifecycle operations like clear and refresh still need their own design for multi-tab behavior:

• one tab may remove and recreate a collection
• other tabs may still hold stale JS RxCollection references
• local-only observables like collections$ are not enough by themselves for cross-tab coordination

Goal

Design and implement a robust cross-tab coordination model for collection reset flows so that when one tab clears/recreates a collection, other tabs either:

• safely rebind to the new collection instance, or
• gracefully soft-reload / recover without data corruption or broken queries

Suggested investigation topics

• current use of collection.onRemove() and other lifecycle hooks
• whether to coordinate via BroadcastChannel, RxState, or another shared channel
• how non-originating tabs discover reset completion and reacquire fresh collection instances
• timeout / failure / retry behavior
• UX when recovery is not immediate
• whether closeDuplicates is compatible with supported multi-tab POS usage

Acceptance criteria

• documented expected behavior for clear-and-refresh with 2+ open tabs
• explicit coordination protocol for reset lifecycle events
• recovery path for non-originating tabs
• tests or manual verification steps covering multi-tab scenarios