fix(cli): give actionable error when 'deep' runs without cli extra (#594)

[uttam12331]

Summary

Fixes #594.

The deep console script is declared in [project.scripts] and is therefore always installed, but its runtime dependencies (click, and pyyaml for YAML files) live in the optional cli extra. On a default install, running deep immediately imported deepdiff.commands, which does import click at module load, so the command died with a raw traceback:

$ uv tool install deepdiff
$ deep --help
Traceback (most recent call last):
  ...
  File ".../deepdiff/commands.py", line 1, in <module>
    import click
ModuleNotFoundError: No module named 'click'

Change

Point the entry point at a thin wrapper (deepdiff/cli.py:main) that checks for click first and, if it's missing, exits with an actionable message instead of a traceback:

$ deep --help
The 'deep' command line tool requires extra dependencies that are not installed.
Install them with:

    pip install deepdiff[cli]

When click is present, the wrapper simply defers to the existing deepdiff.commands.cli group, so behavior is unchanged for anyone who installed deepdiff[cli]. This keeps the CLI dependencies optional (as intended by the cli extra) rather than promoting click/pyyaml to core dependencies.

Tests

Added TestCliEntryPoint in tests/test_command.py:

• test_main_runs_cli_when_click_available — the wrapper runs the CLI group normally when click is installed.
• test_main_reports_missing_click_dependency — with click import forced to fail, main() exits with the pip install deepdiff[cli] hint (reproduces cli - Missing dependency 'click' in default installation #594).

Full tests/test_command.py suite passes (25 passed). Also verified end-to-end in a fresh venv without the cli extra: deep now prints the hint and exits 1 instead of raising ModuleNotFoundError.