test: increase code coverage by adding utility module tests

[katspaugh]

Summary

• Add 110 new unit tests covering 5 previously untested utility modules
• Increase overall code coverage from 30.67% to 36.03% (+5.36pp)
• Achieve 98.29% coverage for the src/utils directory

Test Coverage Details

New Test Files Created

1. argument-parser.test.ts (40 tests)

   • Parsing owners, JSON arguments, addresses, function calls, numeric values, and chain IDs
   • Coverage: 98.23%

2. command-helpers.test.ts (27 tests)

   • Wallet/chain validation, error handling, password prompts, and output formatting
   • Coverage: 100%

3. safe-helpers.test.ts (16 tests)

   • Safe selection, owner verification, address parsing, and transaction selection
   • Coverage: 100%

4. password-handler.test.ts (18 tests)

   • Password retrieval from various sources (env, file, CLI, prompt)
   • Coverage: 100%

5. command-context.test.ts (9 tests)

   • Command context initialization
   • Coverage: 100%

Test Quality

• ✅ All tests passing (931 total tests)
• ✅ Proper mocking of external dependencies (@clack/prompts, fs, process)
• ✅ Coverage of edge cases and error conditions
• ✅ Testing of both success and failure scenarios

Test plan

• All existing tests pass
• New tests pass
• Type check passes
• Linting passes
• Coverage report shows improvement

🤖 Generated with Claude Code

[Copilot]

Pull Request Overview

This PR adds comprehensive unit test coverage for utility functions in the Safe CLI. The tests validate helper functions for Safe account selection, transaction handling, password management, command utilities, context creation, and argument parsing.

• Adds test coverage for safe-helpers utility functions (safe selection, owner validation, transaction selection)
• Adds test coverage for password-handler utility (environment variables, file reading, CLI arguments, security warnings)
• Adds test coverage for command-helpers utility (wallet/chain validation, error handling, password prompts, output formatting)
• Adds test coverage for command-context creation and initialization
• Adds test coverage for argument-parser utility (owners, JSON, addresses, function calls, numeric values, chain IDs)

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/tests/unit/utils/safe-helpers.test.ts	Tests for Safe selection, owner fetching, wallet validation, address parsing, and transaction selection functions
src/tests/unit/utils/password-handler.test.ts	Tests for password retrieval from various sources (env vars, files, CLI), security validation, and environment variable constants
src/tests/unit/utils/command-helpers.test.ts	Tests for wallet/chain validation, error handling, cancellation checks, password prompts, and output formatting functions
src/tests/unit/utils/command-context.test.ts	Tests for command context creation and service initialization
src/tests/unit/utils/argument-parser.test.ts	Tests for parsing various argument types including owners, JSON, addresses, function calls, and numeric/chain values

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