Add Windows (PowerShell) support

- scripts/setup.ps1, scripts/pull-models.ps1, run.ps1 — PowerShell equivalents
  of the bash setup/pull/run scripts
- README + docs/DEPLOY.md: Windows quickstart and Task Scheduler autostart

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

scripts/setup.ps1

@@ -0,0 +1,37 @@
+# One-time setup on Windows: create the Python 3.12 venv and install LiteLLM + Pillow.
+# The router itself is stdlib-only; this is for the LiteLLM backend.
+#   Run:  powershell -ExecutionPolicy Bypass -File .\scripts\setup.ps1
+$ErrorActionPreference = "Stop"
+Set-Location (Split-Path $PSScriptRoot -Parent)   # repo root
+
+function Find-Py312 {
+    if (Get-Command py -ErrorAction SilentlyContinue) {
+        try { if ((& py -3.12 --version 2>&1) -match "3\.12") { return @("py", "-3.12") } } catch {}
+    }
+    foreach ($c in @("python3.12", "python")) {
+        if (Get-Command $c -ErrorAction SilentlyContinue) {
+            try { if ((& $c --version 2>&1) -match "3\.12") { return @($c) } } catch {}
+        }
+    }
+    return $null
+}
+
+$py = Find-Py312
+if (-not $py) {
+    Write-Error "Python 3.12 not found. Install it:  winget install Python.Python.3.12   (or python.org)"
+    exit 1
+}
+$exe = $py[0]
+$baseArgs = if ($py.Count -gt 1) { $py[1..($py.Count - 1)] } else { @() }
+Write-Host ">> using Python 3.12 via '$($py -join ' ')'"
+
+if (-not (Test-Path ".venv")) { & $exe @baseArgs -m venv .venv }
+$vpy = ".\.venv\Scripts\python.exe"
+& $vpy -m pip install -q --upgrade pip
+& $vpy -m pip install -q -r requirements.txt
+& $vpy -c "import litellm, PIL; print('>> deps OK (litellm, pillow)')"
+
+Write-Host ""
+Write-Host "Next:"
+Write-Host "  .\scripts\pull-models.ps1    # pull a model fleet (edit the list first)"
+Write-Host "  .\run.ps1                    # start LiteLLM + router"