feat: enable 'always approve for session' for runtime tools

Runtime tool permission requests (read, write, shell, store_memory) now
resolve stable approval names via fallback in the sidecar approval
coordinator, enabling the 'Always approve' button and session-level
auto-approval for built-in tools.

Backend:
- Add fallback tool names for PermissionRequestRead (read),
  PermissionRequestWrite (write), PermissionRequestShell (shell),
  and PermissionRequestMemory (store_memory)
- Add autoApprovedToolName parameter to RequiresToolCallApproval
  for permission-kind-based session approval matching
- Track tool.execution_start events in ToolNamesByCallId for
  supplementary exact-name resolution

Frontend:
- Use approval.toolName ?? approval.permissionKind as fallback key
  in resolveSessionApproval and ApprovalBanner
- Add shell, read, write permission-kind entries to builtin approval
  tool definitions so pruning preserves session overrides

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

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

@@ -58,6 +58,31 @@ public sealed class CopilotTurnExecutionStateTests
         Assert.Equal("agent-1", observedAgent.AgentId);
     }
 
+    [Fact]
+    public void ObserveSessionEvent_ToolExecutionStart_TracksToolNameByCallId()
+    {
+        RunTurnCommandDto command = CreateCommand();
+        CopilotTurnExecutionState state = new(command);
+
+        state.ObserveSessionEvent(
+            command.Pattern.Agents[0],
+            SessionEvent.FromJson(
+                """
+                {
+                  "type": "tool.execution_start",
+                  "data": {
+                    "toolCallId": "tool-call-1",
+                    "toolName": "view"
+                  },
+                  "id": "33333333-3333-3333-3333-333333333333",
+                  "timestamp": "2026-03-27T00:00:00Z"
+                }
+                """));
+
+        Assert.True(state.ToolNamesByCallId.TryGetValue("tool-call-1", out string? toolName));
+        Assert.Equal("view", toolName);
+    }
+
     [Fact]
     public async Task EmitThinkingIfNeeded_DoesNotDuplicateQueuedThinkingActivity()
     {