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.

gpu-rent.ps1

@@ -73,17 +73,25 @@ if ($needInstall) {
     Get-Date -Format o | Set-Content -LiteralPath $Stamp -Encoding ascii
 }
 
-$GpuHome = Join-Path $env:USERPROFILE ".gpu-rent"
-$EnvFile = Join-Path $GpuHome ".env"
+$EnvFile = Join-Path $Root ".env"
 $Example = Join-Path $Root "env.example"
 if (-not (Test-Path -LiteralPath $EnvFile)) {
-    New-Item -ItemType Directory -Force -Path $GpuHome | Out-Null
     if (Test-Path -LiteralPath $Example) {
         Copy-Item -LiteralPath $Example -Destination $EnvFile
-        Write-Host "gpu-rent: created $EnvFile - fill OS_* (docs/setup.md)"
+        Write-Host "gpu-rent: created .env - fill OS_* (docs/setup.md)"
     }
 }
 
+function Copy-IfMissing {
+    param([string]$Src, [string]$Dst, [string]$Label)
+    if ((Test-Path -LiteralPath $Src) -and -not (Test-Path -LiteralPath $Dst)) {
+        Copy-Item -LiteralPath $Src -Destination $Dst
+        Write-Host "gpu-rent: created $Label"
+    }
+}
+Copy-IfMissing (Join-Path $Root "models.example.yaml") (Join-Path $Root "models.yaml") "models.yaml"
+Copy-IfMissing (Join-Path $Root "extensions.example.yaml") (Join-Path $Root "extensions.yaml") "extensions.yaml"
+
 $ErrorActionPreference = "Continue"
 & $VenvPy -m gpu_rent @args
 exit $LASTEXITCODE