docs(readme): add Windows PowerShell block to Individual services

Only had the Linux venv-activate + uvicorn commands; mirrors the
bash/powershell pairing already used in the Promethean section below.

README.md

@@ -148,6 +148,7 @@ does all inference over HTTP).
 ### Individual services
 
 ```bash
+# Linux
 source Promethean/bin/activate
 
 uvicorn synapse.main:sio_app          --host 0.0.0.0 --port 8000 --reload   # backend (serves the UI too)
@@ -158,6 +159,14 @@ uvicorn synapse.memory.service:app    --host 0.0.0.0 --port 8001 --reload   # me
 cd interface/web && npm run dev
 ```
 
+```powershell
+# Windows — needs the RemoteSigned policy from the Quick start step above
+Promethean\Scripts\Activate.ps1
+
+uvicorn synapse.main:sio_app          --host 0.0.0.0 --port 8000 --reload   # backend (serves the UI too)
+uvicorn synapse.memory.service:app    --host 0.0.0.0 --port 8001 --reload   # memory
+```
+
 ### Promethean
 
 The name for the Python virtual environment all backend code runs in — keeps