Add x-cmd to the Frameworks list.

[lunrenyi]

Description

Added x-cmd to the list, x-cmd is a toolset implemented using posix shell and awk. It is very small in size and offers many interesting features. Here is a milestone demo: https://x-cmd.com/

Tools Provided by x-cmd:

• Wrappers for Common Commands (e.g., cd, ip, ps, tar, apt, brew): These wrapped commands are more intelligent and easier to use compared to the native commands.
• Lightweight Package Management Tool: We have implemented a lightweight package management tool using shell and awk. Through it, you can quickly obtain most common software tools, such as jq, 7za, bat, nvim, python, node, go, etc.
• CLI for Useful Websites (e.g., github.com, cht.sh): We have wrapped their APIs using shell and awk for daily use and to obtain corresponding services in scripts.
• AI Tools: We provide CLIs for ChatGPT, Gemini, Jina.ai, etc., and have wrapped corresponding shortcut commands for different application scenarios, such as @gemini for chatting with Gemini AI and @zh for using AI to translate specified content or command results.

Type of changes

• [ ] A link to an external resource like a blog post
• [x] Add/remove/update a link to a framework
• [ ] Add/remove/update a link to a plugin
• [ ] Add/remove/update a link to a tab completion
• [ ] Add/remove/update a link to a theme
• [ ] Text cleanups/typo fixes

Copyright Assignment

• [x] This document is covered by the BSD License, and I agree to contribute this PR under the terms of the license. This is for the list submission, not for the project(s) you're adding, I don't care what license the plugins have as long as they have something.

Checklist

• [x] I have read the CONTRIBUTING document.
• [x] All new and existing tests passed.
• [x] I have confirmed that the link(s) in my PR is valid.
• [x] I have signed off my commits. You can use git commit --amend --no-edit --signoff to amend an existing commit, and you can find more details about signing off commits on the DCO GitHub action page here.
• [x] My entries are single lines and are in the appropriate (plugins, themes, or completions) section, and in alphabetical order in their section.
• [x] The completion/plugin/theme has a plugin file in the repository that conforms to the ZSH Plugin Standard - TLDR, there's a plugin file with a .plugin.zsh, .zsh or .sh suffix, it is not just bare instructions to be added to .zshrc
• [x] Any added completions have a readme and a license file in their repository.
• [x] Any added frameworks have a readme and a license file in their repository.
• [x] Any added plugins have a readme and a license file in their repository.
• [x] Any added themes have a screenshot, a readme, and a license file in their repository.
• [x] I have stripped any leading and/or trailing zsh-, zsh-plugin and/or oh-my-zsh- substrings from the link's displayed name. This makes it easier to find plugins/themes/completions by name by preventing big clusters in the O and Z sections of the list.