Refactor environment and configuration management

- Updated the project structure to store configuration files (.env, models.yaml, extensions.yaml) in the project root instead of the user's home directory.
- Enhanced the setup process to automatically copy example files to the project root on first run.
- Implemented a migration function to transfer legacy configuration files from the user's home directory to the new project structure.
- Revised documentation to reflect changes in file locations and setup instructions.
- Improved code readability and maintainability by refactoring path management functions.

docs/architecture.md

@@ -7,7 +7,7 @@
 │  gpu-rent CLI                                                 │
 │    up / stop / status / doctor / hold                         │
 │    tunnel / open          — SSH localhost:17801 → VM :7801    │
-│    state ~/.gpu-rent/state.json                               │
+│    state <repo>/.gpu-rent/state.json                          │
 │                                                               │
 │  браузер / MCP / curl API →  http://127.0.0.1:17801           │
 │  локальный SwarmUI        →  http://127.0.0.1:7801  (не трогаем)
@@ -169,5 +169,5 @@ Reconcile: сервер с тегом `gpu-rent` есть, локального
 | --- | --- |
 | Python 3.11+ | openstacksdk, paramiko, Typer, Rich, questionary, dotenv |
 | SSH | paramiko + sshtunnel (Windows без системного `ssh -L`) |
-| Конфиг | `%USERPROFILE%\.gpu-rent\.env` |
+| Конфиг | `<repo>/.env` + runtime в `<repo>/.gpu-rent/` |
 | Лицензия | MIT |