cli: add dump-x11 command

[mahkoh]

No description provided.

[Copilot]

Pull Request Overview

Adds a new CLI subcommand to dump the current X11 keymap and refactors formatting options into a reusable struct.

• Introduces DumpX11 subcommand to fetch and print the XKB keymap from the X server.
• Extracts formatting-related flags into a new FormatArgs and updates existing compile commands to use it.
• Adds x11rb dependency and enables kbvm's x11 feature.

Reviewed Changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
kbvm-cli/src/main.rs	Registers the new dump_x11 module.
kbvm-cli/src/dump_x11.rs	Implements the DumpX11 command: connects to X11, enables XKB, fetches the keymap, and prints it.
kbvm-cli/src/compile_xkb.rs	Switches to FormatArgs for output formatting.
kbvm-cli/src/compile_rmlvo.rs	Switches to FormatArgs for output formatting.
kbvm-cli/src/cli.rs	Adds DumpX11 subcommand (unix-only) and introduces FormatArgs with an apply method.
kbvm-cli/Cargo.toml	Adds x11rb dependency and kbvm x11 feature.

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[Copilot]

Pull Request Overview

Copilot reviewed 6 out of 7 changed files in this pull request and generated no new comments.

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