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>

README.md

@@ -61,6 +61,13 @@ git clone <your-fork-url> llm-router && cd llm-router
 ./run.sh
 ```
 
+On **Windows** (PowerShell), use the `.ps1` equivalents:
+```powershell
+powershell -ExecutionPolicy Bypass -File .\scripts\setup.ps1
+powershell -ExecutionPolicy Bypass -File .\scripts\pull-models.ps1
+powershell -ExecutionPolicy Bypass -File .\run.ps1
+```
+
 Then point any OpenAI client at `http://localhost:8080/v1` with `model: "auto"`:
 
 ```bash