feat(core-backend): add debouncer system notifications in AccountActivity

[Kriys94]

Explanation

Without Debouncer: https://www.loom.com/share/e96ef8f592254e9baaad15e86e823fa4

With Debouncer: https://www.loom.com/share/eddb747eb72b4a6eb8e880e9a942ac12

References

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them

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Note

Medium Risk
Changes real-time chain status signaling timing and payload shape for downstream listeners (e.g. polling coordination); disconnect path behavior is intentionally altered to drop pending ups.

Overview
AccountActivityService no longer publishes AccountActivityService:statusChanged on every system notification. Incoming chain up/down updates are buffered per chain, the flush timer resets on each notification (1s base + up to 1s random jitter), and flush emits at most one batched event per status (up and down separately) with merged chainIds. Debounced publishes no longer include timestamp (disconnect-driven down events still can).

Pending buffers and timers are cleared on WebSocket disconnect (so stale up events are not emitted after a disconnect down flush) and cancelled in destroy(). Changelog documents the behavior change; tests use fake timers for batching, timer reset, jitter, disconnect, and destroy.

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Disconnect drops pending chain downs

High Severity

#chainsUp is updated immediately on each system notification, but statusChanged is only published after the debounce window. On disconnect, buffered changes are cleared and only remaining #chainsUp entries are marked down. Chains that flipped to down inside the window are already removed from #chainsUp, so their pending down is discarded and never published. Consumers such as TokenBalancesController can keep treating those chains as up (slow websocket polling) through an outage, when downs and disconnects often arrive together.

Additional Locations (1)

• packages/core-backend/src/ws/AccountActivityService.ts#L453-L462

 

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