Pin ArgoCD to v3.2.6 (#44)

## Summary
- Pin ArgoCD kustomization to v3.2.6 tag instead of `stable` branch
- This gives intentional control over ArgoCD version upgrades

## Deployment and Testing
- [ ] Sync the `apps` application: `argocd app sync apps`
- [ ] Point argocd at feature branch: `argocd app set argocd --revision feature/pin-argocd-v3.2.6`
- [ ] Sync argocd: `argocd app sync argocd`
- [ ] Verify ArgoCD is running v3.2.6
- [ ] After merge, reset to main: `argocd app set argocd --revision main && argocd app sync argocd`

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Reviewed-on: https://forge.tail8d86e.ts.net/eblume/blumeops/pulls/44

argocd/manifests/kiwix/deployment.yaml

@@ -52,7 +52,7 @@ spec:
 
         # Sidecar: Syncs declarative ZIM torrents to transmission
         - name: torrent-sync
-          image: lscr.io/linuxserver/transmission:latest  # Has transmission-remote CLI
+          image: lscr.io/linuxserver/transmission:4.0.6  # Has transmission-remote CLI
           command: ["/bin/bash", "-c"]
           args:
             - |