Add Docker install instructions and WSL2 troubleshooting

- Add Docker section to quickstart with basic run command
- Document Windows WSL2 networking configuration needed for UDP
- Include Hyper-V firewall fix for peer-to-peer connections

Thanks to fluffomat for diagnosing and documenting the WSL2 fix.

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

Author: sanity

hugo-site/content/quickstart/_index.md

@@ -36,6 +36,16 @@ cargo install freenet
 
 Then start Freenet with `freenet network`.
 
+### Docker
+
+Freenet provides official Docker images. Pull and run with:
+
+```bash
+docker run -p 50509:50509 -p 56208:56208/udp freenetorg/freenet:latest
+```
+
+**Windows (WSL2) users:** Docker Desktop on Windows requires additional configuration for UDP networking. See the [Windows WSL2 Setup](#windows-wsl2-docker-setup) section in Troubleshooting below.
+
 ## Step 2: Join Freenet Official
 
 Get an invite to our community chat. You can request up to 5 invites per day.
@@ -50,6 +60,39 @@ If you run into problems, join our [Matrix chat](https://matrix.to/#/#freenet-lo
 
 **Network requirements:** Freenet uses UDP hole punching for peer-to-peer connections. Most home routers support this without configuration. Strict corporate firewalls may block connections.
 
+### Windows WSL2 Docker Setup
+
+Docker Desktop on Windows uses WSL2, which has networking layers that can block Freenet's UDP peer-to-peer connections. If River won't load or gets stuck at "Subscribing to room", follow these steps:
+
+**1. Configure WSL2 networking**
+
+Create or edit `%USERPROFILE%\.wslconfig` with:
+
+```ini
+[wsl2]
+networkingMode=Mirrored
+firewall=false
+
+[experimental]
+hostAddressLoopback=true
+```
+
+**2. Allow UDP through the Hyper-V firewall**
+
+Open PowerShell as Administrator and run:
+
+```powershell
+Set-NetFirewallHyperVVMSetting -Name '{40E0AC32-46A5-438A-A0B2-2B479E8F2E90}' -DefaultInboundAction Allow
+```
+
+**3. Restart WSL**
+
+```powershell
+wsl --shutdown
+```
+
+Then restart Docker Desktop.
+
 ## What's Next?
 
 - [Live Network Dashboard](http://nova.locut.us:3133/) - Watch real-time activity on the network