implement head and tail commands in command line shell

[AlixANNERAUD]

This pull request adds support for the head and tail commands to the shell, allowing users to view the first or last N lines of a file, similar to their Unix counterparts. It introduces new command implementations, integrates them into the command resolution and dispatch system, and provides comprehensive tests for both commands. Additionally, there is a small fix in the argument parsing macro to improve positional argument handling.

New command implementations:

• Added HeadCommand and TailCommand in head.rs and tail.rs, with logic to read the first or last N lines of a file, including robust handling of edge cases (e.g., files without trailing newlines, zero lines requested). Both commands support -n/--lines option for specifying the number of lines. [1] [2]

Command system integration:

• Registered the new commands in the command module, updated the UserCommandKind enum, and extended the command resolution and dispatch logic to support head and tail. [1] [2] [3] [4] [5]
• Added tests to verify command resolution for head and tail by name.

Testing and robustness:

• Included comprehensive unit tests for both head and tail logic, covering various cases such as files with/without trailing newlines, zero lines requested, and argument parsing. [1] [2]
• Added a new test for graphical shell argument parsing to ensure the --show-keyboard flag is handled correctly.

Macro improvement:

• Improved the executable macro's argument parsing: replaced .next_positional() with .value() for better error handling and correctness when extracting positional arguments.

[codecov]

Codecov Report

❌ Patch coverage is 42.12766% with 136 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...xecutables/shell/command_line/src/commands/head.rs	37.50%	70 Missing ⚠️
...xecutables/shell/command_line/src/commands/tail.rs	40.74%	64 Missing ⚠️
executables/shell/command_line/src/commands/mod.rs	75.00%	2 Missing ⚠️

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