chore: prevent DB race on Keymaster

[Bushstar]

• Resolves: Prevent keymaster race condition on wallet #1019

[Copilot]

Pull Request Overview

This PR prevents database race conditions in Keymaster by implementing a centralized wallet mutation mechanism with locking. The changes address potential concurrency issues where multiple operations could modify the wallet simultaneously, ensuring thread-safe operations through an abstract base class with built-in locking.

• Introduces AbstractBase class with a promise-based locking mechanism for wallet operations
• Refactors all wallet storage classes to extend AbstractBase instead of implementing WalletBase directly
• Replaces direct load/modify/save patterns with atomic mutateWallet operations throughout Keymaster

Reviewed Changes

Copilot reviewed 15 out of 16 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
packages/keymaster/src/db/abstract-base.ts	New abstract base class providing thread-safe updateWallet method with promise-based locking
packages/keymaster/src/types.ts	Adds updateWallet method to WalletBase interface
packages/keymaster/src/keymaster.ts	Refactors wallet operations to use new mutateWallet helper for atomic updates
packages/keymaster/src/db/*.ts	Updates all wallet storage implementations to extend AbstractBase
tests/keymaster/wallet.test.ts	Adds test coverage for new functionality
packages/keymaster/rollup.cjs.config.js	Adds build configuration for new abstract base module

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[macterra]

Just for the record, no material change to keymaster service performance (using json db). Running ./kc perf-test 1000 took ~22s before, now 25s.