fix(config): ensure --confDir is globally respected and add integration tests

[vikram-2101]

Summary

This PR fixes the configuration path propagation issue where the --confDir flag was not respected globally. Previously, some operations such as save() and logout could fall back to the default configuration directory instead of the user-provided one.

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Changes

• Ensured the configuration directory used during load() is preserved and reused by save() operations.
• Simplified startup.ts by delegating default path handling to load().
• Added integration tests to verify --confDir behavior.
• Added a new test verifying logout using --confDir.
• Improved some integration tests to avoid fragile exact string matching

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Verification

• Ran npm test in WSL.
• Confirmed integration tests pass when using a custom --confDir.