feat: introduce MCP server, cross-platform runtime, and Showcase UI reorganization

- Showcase UI Reorganization:
  * Move web UI dashboard from root directory into apps/showcase_ui/ for cleaner project structure
  * Add 'artemis ui' CLI command (artemis/interfaces/cli/commands/ui.py) and launcher scripts for the interactive showcase console
- Standalone MCP Server & Notifiers (mcp_server/):
  * Implement dedicated MCP server package with mobile automation tools (device_state, inspect_trace, task_manager, task_runner)
  * Add multi-channel notifiers (AgentAPI, Desktop notifications, Webhooks, File output, and Composite routing)
  * Introduce background task runner and trace store for autonomous mobile execution monitoring
- Cross-Platform Runtime & Toolchain Support:
  * Add artemis/platform/ with OS-specific implementations for Linux, macOS (Darwin), and Windows
  * Add artemis/runtime/supervisor.py for resilient process and agent runtime supervision
  * Add artemis/toolchain/ with dependency resolution and SDK descriptors
  * Add cross-platform launcher scripts (start.sh, start.bat) and installer scripts (scripts/install_deps.*)
- Core Enhancements & Diagnostics:
  * Enhance coordinate normalization, OCR API fallback, and perception pipeline
  * Add credential validation (credentials_validator.py) and system diagnostics
  * Update bilingual documentation (README.md, README_CN.md) and architecture diagrams
- Test Suite Expansion:
  * Add integration tests for cloud gateway, remote ADB, and Artemis login
  * Add unit tests covering core diagnostics, platform detection, toolchain, credentials validator, optional OCR, and MCP tools

tests/unit/mcp/test_mcp_tools.py

@@ -0,0 +1,113 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Unit tests for Artemis MCP Tools."""
+
+import inspect
+import shutil
+import tempfile
+import uuid
+import pytest
+
+from mcp_server.tools import (
+    mobile_get_device_state,
+    mobile_inspect_trace,
+    mobile_manage_task,
+    mobile_run_task,
+)
+from mcp_server.utils import trace_store
+
+
+@pytest.fixture
+def temp_trace_env(monkeypatch):
+    temp_dir = tempfile.mkdtemp()
+    monkeypatch.setattr(trace_store, "TRACES_DIR", temp_dir)
+    yield temp_dir
+    shutil.rmtree(temp_dir, ignore_errors=True)
+
+
+def test_tool_signatures():
+    # mobile_run_task signature check
+    sig_run = inspect.signature(mobile_run_task)
+    assert "task_desc" in sig_run.parameters
+    assert "conversation_id" in sig_run.parameters
+    assert "model" in sig_run.parameters
+    assert "locked_app_package" in sig_run.parameters
+    assert "app_path" in sig_run.parameters
+    assert "expected_output_desc" in sig_run.parameters
+
+    # mobile_manage_task signature check
+    sig_manage = inspect.signature(mobile_manage_task)
+    assert "action" in sig_manage.parameters
+    assert "trace_id" in sig_manage.parameters
+    assert "instruction" in sig_manage.parameters
+
+    # mobile_get_device_state signature check
+    sig_device = inspect.signature(mobile_get_device_state)
+    assert "view_type" in sig_device.parameters
+
+    # mobile_inspect_trace signature check
+    sig_inspect = inspect.signature(mobile_inspect_trace)
+    assert "action" in sig_inspect.parameters
+    assert "trace_id" in sig_inspect.parameters
+    assert "step_number" in sig_inspect.parameters
+
+
+def test_mobile_run_task_invalid_model():
+    with pytest.raises(ValueError, match="Invalid model"):
+        mobile_run_task(task_desc="test", conversation_id="conv-1", model="invalid_model")
+
+
+def test_mobile_manage_task_unknown_trace(temp_trace_env):
+    res = mobile_manage_task(action="status", trace_id="non-existent-trace")
+    assert res["status"] == "unknown"
+    assert "not found" in res["message"]
+
+
+def test_mobile_manage_task_status_and_stop(temp_trace_env):
+    trace_id = str(uuid.uuid4())
+    trace_store.init_trace(trace_id, "Test task", "Flash", "conv-1")
+
+    # Status check
+    status_res = mobile_manage_task(action="status", trace_id=trace_id)
+    assert status_res["trace_id"] == trace_id
+    assert status_res["status"] == "running"
+    assert status_res["model"] == "Flash"
+
+    # Stop without PID
+    stop_res = mobile_manage_task(action="stop", trace_id=trace_id)
+    assert stop_res["trace_id"] == trace_id
+    assert "PID" in stop_res["message"] or "Cannot stop" in stop_res["message"]
+
+
+def test_mobile_manage_task_inject_instruction(temp_trace_env):
+    trace_id = str(uuid.uuid4())
+    trace_store.init_trace(trace_id, "Test task", "Pro", "conv-1")
+
+    # Missing instruction parameter
+    err_res = mobile_manage_task(action="inject_instruction", trace_id=trace_id)
+    assert "Missing required argument" in err_res["message"]
+
+    # Valid injection
+    ok_res = mobile_manage_task(
+        action="inject_instruction", trace_id=trace_id, instruction="Scroll down slowly"
+    )
+    assert "Successfully injected" in ok_res["message"]
+
+
+@pytest.mark.asyncio
+async def test_mobile_inspect_trace_invalid_action():
+    res = await mobile_inspect_trace(action="invalid_action", trace_id="trace-123")
+    assert "error" in res
+    assert "not supported" in res["message"]