feat: add PyInstaller build for standalone binary distribution

- Add PyInstaller spec file and build script for creating standalone executables
- Add install.sh for curl | sh installation from GitHub releases
- Add GitHub Actions workflow for multi-platform builds (macOS, Linux, Windows)
- Move sandbox-only deps (playwright, ipython, libtmux, etc.) to optional extras
- Make google-cloud-aiplatform optional ([vertex] extra) to reduce binary size
- Use lazy imports in tool actions to avoid loading sandbox deps at startup
- Add -v/--version flag to CLI
- Add website and Discord links to completion message
- Binary size: ~97MB (down from ~120MB with all deps)

containers/Dockerfile

@@ -158,7 +158,7 @@ RUN mkdir -p /workspace && chown -R pentester:pentester /workspace /app
 COPY pyproject.toml poetry.lock ./
 
 USER pentester
-RUN poetry install --no-root --without dev
+RUN poetry install --no-root --without dev --extras sandbox
 RUN poetry run playwright install chromium
 
 RUN /app/venv/bin/pip install -r /home/pentester/tools/jwt_tool/requirements.txt && \