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

mcp_server/tools/device_state.py

@@ -0,0 +1,104 @@
+# 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.
+
+"""MCP Tool: mobile_get_device_state."""
+
+import base64
+import os
+
+from mcp_server.base import mcp
+from artemis.mcp.adb_server import _get_controller
+from mcp_server.utils import env_utils
+from artemis.utils.ocr_xml_fusion import (
+    fuse_ocr_with_xml,
+    _detect_status_bar_height,
+    _crop_image_remove_status_bar,
+    _map_coordinates_back,
+)
+from artemis.utils.ocr_api import perform_ocr
+from artemis.utils.visualization import format_minimal_list_with_elements
+
+
+@mcp.tool()
+async def mobile_get_device_state(view_type: str) -> str:
+    """Real-time mobile device state observer (for debugging and validation).
+
+    Use this tool to inspect the latest mobile status or to assist in tracking
+    the subagent's task progress.
+
+    Retrieves a real-time screenshot (returns local file URI) or a simplified
+    element tree text list of the currently connected mobile device.
+
+    Args:
+        view_type: The observation type. Supported values: - "screenshot":
+          Captures the real-time mobile screen and saves it to the workspace,
+          returning the local URI path of the image file (e.g.,
+          "file:///path/to/screenshot.jpg"). - "hierarchy": Directly returns the
+          simplified text-labeled element list, which is identical to what the
+          mobile UI automation subagent sees when making decisions.
+    """
+    try:
+        controller = _get_controller()
+        device_width = controller.ctx.device.device_width
+        device_height = controller.ctx.device.device_height
+    except Exception as e:
+        return f"Error: Failed to initialize/lock Android device controller: {e}"
+
+    try:
+        device_data = await controller.get_screen_data()
+        latest_screenshot_b64 = device_data.base64
+        xml_hierarchy = device_data.elements
+
+        project_root = env_utils.get_project_root()
+
+        if view_type == "screenshot":
+            screenshot_bytes = base64.b64decode(latest_screenshot_b64)
+            device_id = controller.ctx.device.device_id
+            safe_device_id = "".join(
+                [c if c.isalnum() or c in ("-", "_") else "_" for c in device_id]
+            )
+            screenshot_filename = f"live_screenshot_{safe_device_id}.jpg"
+            screenshot_path = os.path.join(project_root, screenshot_filename)
+
+            with open(screenshot_path, "wb") as f:
+                f.write(screenshot_bytes)
+
+            return f"file://{screenshot_path}"
+
+        elif view_type == "hierarchy":
+            try:
+                screen_height = device_data.height
+                status_bar_height = _detect_status_bar_height(xml_hierarchy, screen_height)
+                if status_bar_height > 0:
+                    cropped_b64, _, _ = _crop_image_remove_status_bar(
+                        latest_screenshot_b64, status_bar_height
+                    )
+                    raw_ocr_results = await perform_ocr(cropped_b64)
+                    ocr_results = _map_coordinates_back(raw_ocr_results, status_bar_height)
+                else:
+                    ocr_results = await perform_ocr(latest_screenshot_b64)
+            except Exception:
+                ocr_results = []
+
+            fused_xml = fuse_ocr_with_xml(xml_hierarchy, ocr_results)
+            hierarchy_text, elements, labels = format_minimal_list_with_elements(
+                fused_xml, width=device_width, height=device_height
+            )
+            return hierarchy_text
+
+        else:
+            return f"Error: Invalid view_type '{view_type}'. Supported types are 'screenshot' and 'hierarchy'."
+
+    except Exception as e:
+        return f"Error: An unexpected error occurred while communicating with the device: {e}"