…r recovery (#449)

## Summary

Ledger devices may return signature `v` as 0 or 1 (modern format), but
Ethereum's `ecrecover` expects 27 or 28. This causes `"The signature
doesnt match the right address"` errors in
[`signPersonalMessage`](https://github.com/MetaMask/accounts/blob/main/packages/keyring-eth-ledger-bridge/src/ledger-keyring.ts#L475)
and
[`signTypedData`](https://github.com/MetaMask/accounts/blob/main/packages/keyring-eth-ledger-bridge/src/ledger-keyring.ts#L475).

## Fix

```typescript
if (recoveryParam === 0 || recoveryParam === 1) {
  recoveryParam += 27;
}
```

## Why This Wasn't Fixed Before

**Original bug (pre-2022):** The code *subtracted* 27 from `v`:
```javascript
let v = payload.v - 27  // WRONG
```
This converted correct values (27/28) into incorrect ones (0/1).

**PR #152 (August 2022):** Changed to pass through the raw value:
```javascript
let v = parseInt(payload.v, 10)  // Just pass through
```
This fixed the case where Ledger returns 27/28, but assumed Ledger
*always* returns 27/28.

**The gap:** Ledger devices may return 0/1 depending on firmware,
signing method, or device model. PR #152 didn't normalize these values.

**Issue #10850 was closed prematurely** in January 2024 with "I expect
this was resolved in PR #152" — but PR #152 only fixed one direction of
the problem.

## References

This is a well-known issue with a standard fix across the ecosystem:

- [Frame
wallet](https://github.com/floating/frame/blob/0.6.10/main/provider/helpers.ts#L10)
- `v = v === 0 || v === 1 ? v + 27 : v`
- [Rabby
wallet](https://github.com/RabbyHub/Rabby/blob/develop/src/ui/utils/gnosis.ts)
- *"Metamask with ledger returns V=0/1 here too"*
- [Gnosis Safe
Android](https://github.com/safe-global/safe-android/blob/main/app/src/main/java/io/gnosis/safe/ui/transactions/details/viewmodel/TxReviewViewModel.kt)
- `if (v <= 1) v += 27`
- Related issues:
[eth-ledger-bridge-keyring#134](MetaMask/eth-ledger-bridge-keyring#134),
[eth-ledger-bridge-keyring#151](MetaMask/eth-ledger-bridge-keyring#151),
[metamask-extension#10850](MetaMask/metamask-extension#10850)

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Changes signature formatting in `signPersonalMessage` and
`signTypedData`, which can affect signature verification and downstream
consumers if assumptions about `v` differ. Scope is small and covered by
new unit tests for multiple `v` cases.
> 
> **Overview**
> Fixes Ledger signing to **normalize the recovery param (`v`)** so
devices returning modern values `0/1` are converted to legacy `27/28`
before building the final signature in `ledger-keyring.ts`.
> 
> Adds focused tests covering `v` normalization for both
`signPersonalMessage` and `signTypedData`, and updates the
`CHANGELOG.md` entry accordingly (plus minor Jest coverage threshold
tweaks).
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
e756502. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->