fix(tool): implement tool_type filter in ToolRegistry.list_tools()

The tool_type parameter in ToolRegistry.list_tools() was explicitly
silenced with '_ = tool_type', making it a no-op. Both
'agents tool list --type validation' and 'agents tool list --type tool'
returned the full unfiltered tool list.

Changes:
- src/cleveragents/tool/runtime.py: Add tool_type: Literal['tool',
  'validation'] field to ToolSpec (default 'tool') so the registry
  has a discriminator to filter on.
- src/cleveragents/tool/registry.py: Remove '_ = tool_type' no-op and
  implement actual filter: specs = [s for s in specs if s.tool_type == tool_type].
  Update docstring to reflect the parameter is now active.
- features/consolidated_tool.feature: Add 7 comprehensive Behave
  scenarios covering all filter combinations (tool, validation, None,
  default type, exclusion).
- features/steps/tool_runtime_steps.py: Add step definition for
  registering a ToolSpec with an explicit tool_type.
- robot/helper_tool_cli.py: Add tool_list_type_tool() and
  tool_list_type_validation() helper functions that verify the CLI
  passes tool_type through to the service layer.
- robot/tool_cli.robot: Add two Robot test cases for
  'tool list --type tool' and 'tool list --type validation'.

The CLI handler (cli/commands/tool.py) and database repository
(infrastructure/database/repositories.py) already passed tool_type
through correctly — no changes needed there.

ISSUES CLOSED: #2974

robot/helper_tool_cli.py

@@ -193,9 +193,43 @@ def validation_detach() -> None:
     print("validation-cli-detach-ok")
 
 
+def tool_list_type_tool() -> None:
+    """Verify tool list --type tool returns only tools."""
+    svc = MagicMock()
+    svc.list_tools.return_value = [_mock_tool("local/smoke-tool", "tool")]
+    with patch(
+        "cleveragents.cli.commands.tool._get_tool_registry_service",
+        return_value=svc,
+    ):
+        result = runner.invoke(tool_app, ["list", "--type", "tool"])
+    assert result.exit_code == 0, f"exit={result.exit_code}: {result.output}"
+    svc.list_tools.assert_called_once_with(
+        namespace=None, tool_type="tool", source=None
+    )
+    print("tool-cli-list-type-tool-ok")
+
+
+def tool_list_type_validation() -> None:
+    """Verify tool list --type validation returns only validations."""
+    svc = MagicMock()
+    svc.list_tools.return_value = [_mock_tool("local/smoke-val", "validation")]
+    with patch(
+        "cleveragents.cli.commands.tool._get_tool_registry_service",
+        return_value=svc,
+    ):
+        result = runner.invoke(tool_app, ["list", "--type", "validation"])
+    assert result.exit_code == 0, f"exit={result.exit_code}: {result.output}"
+    svc.list_tools.assert_called_once_with(
+        namespace=None, tool_type="validation", source=None
+    )
+    print("tool-cli-list-type-validation-ok")
+
+
 _COMMANDS = {
     "tool-add-config": tool_add_config,
     "tool-list": tool_list_all,
+    "tool-list-type-tool": tool_list_type_tool,
+    "tool-list-type-validation": tool_list_type_validation,
     "tool-show": tool_show_name,
     "tool-remove": tool_remove_name,
     "validation-add-config": validation_add_config,