Refactor for new workflow schema & plugin management

Major breaking changes:
- Refactor workflow model: add ExecutionConfig & FlowControlConfig, move Parameters/Dependencies, update timeout/delay fields, add agent/branching support.
- Update all workflow UI and logic to use new nested model.
- Remove PluginConfig page/dialogs; unify plugin management under /plugins.
- Simplify plugin install/update/uninstall: version in type string, update dialog fields.
- Update workflow config dialog for new timeout/retry fields.
- Bump to .NET 10.0 and latest NuGet packages.
- Remove obsolete usings, update sample workflow, minor UI tweaks.

Aligns console with latest FlowSynx schema and API.

#90

Author: ziagham

src/Components/Layout/NavMenu.razor

@@ -5,11 +5,7 @@
     <MudDivider />
     <MudNavLink Href="/plugins"
                 Match="NavLinkMatch.Prefix"
-                Icon="@Icons.Material.Filled.GridView">Installed Plugins</MudNavLink>
-    <MudDivider />
-    <MudNavLink Href="/pluginconfig"
-                Match="NavLinkMatch.Prefix"
-                Icon="@Icons.Material.Filled.Settings">Plugins Config</MudNavLink>
+                Icon="@Icons.Material.Filled.GridView">Plugins</MudNavLink>
     <MudDivider />
     <MudNavLink Href="/workflows"
                 Match="NavLinkMatch.Prefix"