PR #3911 changed the browser-use entry point to skill_cli/main.py but
didn't port the early command interception for install, init, --template,
and --mcp. This broke:
- `browser-use install` (installs Chromium via playwright)
- `browser-use init` (generates template files)
- `browser-use --template` (direct template generation)
- `browser-use --mcp` (MCP server mode)
This fix adds early command interception to skill_cli/main.py, matching
the behavior from browser_use/cli.py. Commands are handled before argparse
to avoid loading heavy dependencies for simple setup tasks.
Also adds tests to prevent regression.