Implement unit tests for shared/validators

[b-garbacz]

Prerequisites

#480 #468

Description

Implement comprehensive unit tests for all files in src/core/network/protocols/shared/validators/**.
Cover:

• positive (valid payload) scenarios,
• negative scenarios (invalid/missing fields, wrong types, invalid state conditions),
• boundary/edge cases.

Acceptance Criteria

1. Every validator file in shared/validators has dedicated unit tests.
2. Tests include happy-path, negative, and edge/boundary cases.

Important Note

Many shared validators are state-dependent, not schema-only. Tests should prepare a minimal initial state required for validation (for example admin/writer/whitelist and relevant state entries), similar to existing scenario-based tests in tests/unit/state/** and setup helpers in tests/helpers/setupApplyTests.js.