fix(assets-controller): hardened error handling

[Kriys94]

Explanation

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 request fan-out and concurrency for token metadata and spot-price fetching and alters error propagation by swallowing exceptions in several update callbacks, which could impact refresh behavior and observability if misconfigured.

Overview
Improves assets pipeline resilience by wrapping several push-update callbacks in try/catch (active-chain updates in AssetsController, and polling callbacks in RpcDataSource and StakedBalanceDataSource) to prevent unhandled errors from breaking subscription/poll ticks.

Fixes v3 API request limits by chunking Tokens /v3/assets metadata fetches and Prices v3 spot-price fetches into max 120 asset IDs per request, executing chunks in parallel with bounded concurrency via p-limit; adds unit tests covering chunking behavior (including non-USD + USD dual-fetch). Also hardens SnapDataSource balance update handling against missing/undefined payload fields and updates the mock messenger fixture import path.

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Cursor Bugbot has reviewed your changes and found 1 potential issue.

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Unused MIN_TOKEN_OCCURRENCES constant is dead code

Low Severity

The MIN_TOKEN_OCCURRENCES constant is defined but never referenced anywhere in the codebase. A grep across the entire repository finds only this single definition. The changelog notes that the filtering approach changed from minimum occurrence count to Blockaid scanning, so this constant appears to be a leftover from the old approach that was inadvertently introduced in this diff.