feat(cli): new layout-ratios command

The implementation adds a new layout-ratio CLI command to komorebi that
allows users to dynamically set column and row ratios for layouts at
runtime via komorebic layout-ratio --columns 0.3 0.4 --rows 0.5.

A public validate_ratios function was added to komorebi-layouts that
clamps ratio values between 0.1 and 0.9, truncates when the cumulative
sum would reach or exceed 1.0, and limits to a maximum of 5 ratios. This
function is shared between config file deserialization and the new CLI
command, ensuring consistent validation behavior.

The SocketMessage enum in komorebi/src/core/mod.rs has a new
LayoutRatios variant. The handler in process_command.rs uses the shared
validate_ratios function to process the ratios before applying them to
the focused workspace's layout options.

When the CLI command is called without any arguments, it prints a
helpful message instead of returning an error.

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