fix: formatChainIdToHex returns unprefixed hex

[micaelae]

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

Low Risk
Small utility-level formatting change; main risk is subtle behavior differences for inputs that previously produced non-prefixed hex (or for callers passing undefined to formatAddressToAssetId).

Overview
Fixes chain ID formatting in bridge-controller so EVM chain IDs derived from numbers/strings/CAIP references are converted using numberToHex, ensuring a 0x-prefixed hex output (including when building CAIP chain IDs via formatChainIdToCaip).

Updates formatAddressToAssetId’s signature to require addressOrAssetId (no longer optional), and records the fix in the Unreleased changelog (marking 66.1.0 as deprecated).

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[cursor]

Cursor Bugbot has reviewed your changes and found 2 potential issues.

[cursor]

Malformed chain IDs now parse silently

Low Severity

Replacing toHex with numberToHex(Number(...)) removes strict decimal-string validation. Inputs like scientific-notation strings can now be accepted and reinterpreted as different chain IDs instead of being rejected, so invalid chainId values may silently route to the wrong network.

Additional Locations (1)

• packages/bridge-controller/src/utils/caip-formatters.ts#L54-L55

 

[micaelae]

There is a type check for number so this is ok. Also this is restoring the previous implementation of the formatter