fix(cli): launch subcommands with the active Python interpreter

[imMamdouhaboammar]

Problem

The ga console script can be installed and run from a virtual environment or another explicit Python interpreter, but every Python-based frontend command in ga_cli/cli.py starts with the literal executable name python.

That can resolve to a different interpreter than the one running ga, or fail entirely on systems where only python3 exists. It also conflicts with cmd_update(), which already uses sys.executable correctly.

Fix

Normalize only Python launcher commands inside launch_frontend(): when the command's first token is exactly python, replace it with sys.executable. Non-Python runtimes are left untouched.

This keeps the command registry readable and avoids editing each command definition separately.

Verification

TDD was performed on a separate validation branch:

1. Regression-only GitHub Actions run 31166383679 failed because launch_frontend() passed python instead of the active interpreter path; the non-Python launcher case already passed
2. The minimal dispatcher fix passed run 31166445434: compile, both regression tests, and git diff --check
3. This contribution branch is rebuilt directly from current main as one clean commit with no temporary CI files

Scope

• 1 CLI production file modified
• 1 focused regression-test file added
• 1 clean commit on top of current main
• no dependency or configuration changes