feat(lume): Add option to specify custom config file path

[marksisson]

• Added --config CLI option to allow users to specify custom config file location
• SettingsManager now supports custom config file paths via setCustomConfigPath()
• Custom config path overrides default XDG_CONFIG_HOME location
• Parent directories are created automatically for custom config paths

[coderabbitai]

Important

Review skipped

Auto reviews are limited based on label configuration.

🏷️ Required labels (at least one) (1)

• rabbit

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

• 🔍 Trigger review

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

---

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[vercel]

@marksisson is attempting to deploy a commit to the Cua Team on Vercel.

A member of the Team first needs to authorize it.

[Copilot]

Pull request overview

This PR adds a --config CLI option to allow specifying a custom configuration file path, and updates SettingsManager to read/write settings from that custom path instead of the default XDG-based location.

Changes:

• Added --config option to the root lume command.
• Added support in SettingsManager for a custom config file path and custom parent directory creation.
• Added pre-parse argument scanning to apply the custom config path before command parsing.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 8 comments.

File	Description
libs/lume/src/Main.swift	Adds --config option and early argument scanning to set the config path before parsing.
libs/lume/src/FileSystem/Settings.swift	Adds a custom config path override and adjusts directory creation behavior for saving settings.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[marksisson]

Motivation for pull request:

This provides a mechanism for configuration of Lume without relying on global state of the system, such as environment variables, file system layouts, or implicit paths.

This is very helpful when building "wrappers" that want to invoke lume with a specific configuration, so that is does not rely on global state, e.g. I use nix, and this enables scenarios such as running directly from a remote flake without installing.