fix: filter internal runtime tools

Exclude internal runtime tools from sidecar capability discovery so they do not surface in the approval tool catalog.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

sidecar/tests/Aryx.AgentHost.Tests/SidecarProtocolHostTests.cs

@@ -517,7 +517,7 @@ public sealed class SidecarProtocolHostTests
     }
 
     [Fact]
-    public void MapRuntimeTools_ExcludesAskUserAndDeduplicatesByName()
+    public void MapRuntimeTools_ExcludesInternalToolsAndDeduplicatesByName()
     {
         IReadOnlyList<SidecarRuntimeToolDto> runtimeTools = SidecarProtocolHost.MapRuntimeTools(
         [
@@ -527,6 +527,21 @@ public sealed class SidecarProtocolHostTests
                 Description = "Ask the user a question.",
             },
             new Tool
+            {
+                Name = "report_intent",
+                Description = "Report current intent.",
+            },
+            new Tool
+            {
+                Name = "task_complete",
+                Description = "Signal task completion.",
+            },
+            new Tool
+            {
+                Name = "exit_plan_mode",
+                Description = "Exit plan mode.",
+            },
+            new Tool
             {
                 Name = " web_fetch ",
                 Description = " Fetch content from the web. ",