fix(config): handle directory paths for --config and HARBOR_CLI_CONFIG

[Jay2006sawant]

Description

Briefly describe what this pull request does and why the change is needed.

• Fixes [bug]: Config directory path via --config or HARBOR_CLI_CONFIG corrupts data.yaml and bricks CLI #993

When --config or HARBOR_CLI_CONFIG pointed to a directory (as documented in the README), Harbor CLI persisted that directory path into data.yaml before validating it was a file. This caused a fatal error on every subsequent run until data.yaml was manually repaired.

This PR resolves directory paths to <dir>/config.yaml and ensures the config file is validated before updating data.yaml.

Type of Change

Please select the relevant type.

• Bug fix
• New feature
• Refactor
• Documentation update
• Chore / maintenance

Changes

• Add normalizeConfigPath to resolve directory paths to config.yaml for --config and HARBOR_CLI_CONFIG
• Reorder InitConfig to call EnsureConfigFileExists before ApplyDataFile, preventing invalid paths from being persisted
• Add unit tests for directory-based config paths (Test_Config_EnvVar_Directory, Test_Config_Flag_Directory)

Test plan

• go test ./pkg/utils/... -run Test_Config
• harbor -c ~/.config/harbor-cli version — exits 0, data.yaml stores file path
• HARBOR_CLI_CONFIG=$HOME/.config/harbor-cli harbor version — exits 0
• Subsequent harbor version runs work without manual data.yaml repair