resolveDecryptedValue is not wrapped in try/catch

[manuelwedler]

Problem

All ExternalDataProvider methods are supplied by the wallet and can throw (network errors, rejected signatures, bugs). Every call site in src/formatters.ts wraps the provider call in try/catch and falls back to a warning:

• resolveChainInfo (formatters.ts:171, :271, :798)
• resolveToken (formatters.ts:296, :1161)
• resolveNftCollectionName (formatters.ts:498)
• resolveBlockTimestamp (formatters.ts:587)
• resolveLocalName / resolveEnsName (formatters.ts:1039, :1058)

The one exception is resolveDecryptedValue in decryptFieldValue (src/fields.ts:972). The call is not wrapped. If the wallet callback throws, the error goes up through processSingleField and the whole format() call rejects. Only the later hexToBytes(result.value) has a try.

Expected behavior

Catch a thrown error from resolveDecryptedValue and return a DECRYPTION_FAILED warning, consistent with the other handlers. The field then renders the fallbackLabel / [Encrypted] placeholder with rawEncryptedValue set.

Tasks

• Wrap the resolveDecryptedValue call in src/fields.ts in try/catch and map a throw to DECRYPTION_FAILED.
• Add a test in test/registry-cases/zama/zama.spec.ts for a provider that throws.
• Update CLAUDE.md: document that every ExternalDataProvider call must be wrapped in try/catch because the methods are user-provided and can throw; a throw must become a warning, never a rejected format() call. Add the throw case to the DECRYPTION_FAILED list in the Encrypted Fields section.
• Check GUIDE.md and DECRYPTION.md for statements about error handling of provider methods.