Implement UP_STOP_ON_FAIL option to manage GPU state on installation failure

- Added a new configuration option `UP_STOP_ON_FAIL` to control whether the GPU should be stopped automatically if the `up` command fails, enhancing user control over resource management.
- Updated the CLI to include a `--keep-on-fail` flag, allowing users to prevent GPU shutdown during installation errors.
- Enhanced the installation scripts and documentation to reflect these changes, providing clearer guidance on the new behavior and configuration options.
- Improved error handling in the CLI to ensure proper cleanup of resources in case of failure, preventing unexpected billing for unused GPU resources.

docs/cli.md

@@ -57,6 +57,7 @@ gpu-rent up --yes --ollama
 | `gpu-rent dry-run` | План без mutating-вызовов |
 | `gpu-rent up` | Без `--yes`: меню LLM (если runtime none) → пресет → **Selectel**: flavor # / data GB / preemptible → confirm → create → туннель. Цветной лог (ошибки/warn/ok) |
 | `gpu-rent up --yes` | Без вопросов; flavor из `FLAVOR_PREFERENCE` / `DEFAULT_FLAVOR_ID` |
+| `up --keep-on-fail` | Не гасить GPU при ошибке install (по умолчанию `UP_STOP_ON_FAIL=true` → `stop`) |
 | `gpu-rent up -v` / `--verbose` | Полная таблица doctor на `up` (по умолчанию кратко) |
 | `gpu-rent up --ollama` / `--llamacpp` / `--llm …` | LLM рядом со SwarmUI |
 | `gpu-rent up --no-swarm` / `--llm-only` | Только LLM (нужен `--ollama`/`--llamacpp`); без clone SwarmUI |