feat(cli): add initial CLI implementation with argument parsing and prompt handling

- Created package.json and package-lock.json for CLI package.
- Implemented argument parsing in args.ts to handle various flags and commands.
- Developed main CLI logic in cli.ts to execute commands and handle errors.
- Added configuration loading from a JSON file in config.ts, with environment variable support.
- Implemented prompt resolution and provider interaction in prompt.ts.
- Added usage documentation for the CLI.
- Configured TypeScript settings in tsconfig.json for the CLI package.
- Updated README in vscode package to reflect the new CLI functionality.
- Refactored root tsconfig.json to streamline project structure.

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 LexAI contributors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.