fix(wallets): throw typed InvalidSignerError when removeSigner API call fails

[devin-ai-integration]

Description

When removeSigner receives an error response from the API ("error" in response), it threw new Error(...) — a generic Error that consumers cannot pattern-match by type.

This change makes removeSigner consistent with addSigner by throwing InvalidSignerError with:

• response.message as the human-readable error message
• Full response JSON as details (machine-inspectable via CrossmintSDKError.details)

Also renames the log key to wallet.removeSigner.failed for consistency with wallet.addSigner.failed.

Same error-masking pattern fixed for OTP validation (#1886), get-status (#1896), export-signer (#1897), and addSigner chain failure (#1898).

Test plan

• Existing test suite passes (337 tests including Wallet - removeSigner() suite)
• Lint passes (Biome)
• No new error class — reuses existing InvalidSignerError for consistency with addSigner

Package updates

• @crossmint/wallets-sdk — patch changeset added (fix-removesigner-typed-error.md)

Link to Devin session: https://crossmint.devinenterprise.com/sessions/7bd8230602444a8a94498384e0aac02d
Requested by: @xmint-guille

[devin-ai-integration]

Original prompt from Guille

@skills:cse spotpay reported the following, investigate when this could happen and how should we improve our error client side:
During wallet recovery, complete-onboarding returns OTP validation failed, but the app surfaces it as:
"Crossmint signer returned an internal error"

This happens in the wallet recovery/addSigner path, likely when registering the device signer after auth is required. Logs show:

• wallet.recover.start
• complete-onboarding request
• complete-onboarding: OTP validation failed
• wallet.addSigner threw
• wallet.recover threw
• Error in verifyOtp
• Crossmint signer returned an internal error

The SDK should preserve the underlying auth/OTP failure reason instead of collapsing it into an internal signer error. Also distinguish true user cancellation from failed OTP / recovery errors.
ATTACHMENT:"https://crossmint.devinenterprise.com/attachments/76cc8351-35a7-4370-9a64-206aa1191469/CleanShot+2026-06-02+at+14.08.27%402x.png"

[devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR that start with 'DevinAI' or '@devin'.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

• Disable automatic comment, CI, and merge conflict monitoring

[greptile-apps]

_{Reviews (1): Last reviewed commit: "fix(wallets): throw typed InvalidSignerE..." | Re-trigger Greptile}