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/notifiers/webhook.py

@@ -0,0 +1,87 @@
+# 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.
+
+"""Webhook Notifier for OpenClaw, CI pipelines, and external gateways."""
+
+import json
+import logging
+import os
+import time
+from typing import Any
+import urllib.request
+
+from mcp_server.notifiers.base import BaseNotifier
+
+logger = logging.getLogger("mcp_server.notifiers.webhook")
+
+
+class WebhookNotifier(BaseNotifier):
+    """Notifier that posts execution events to HTTP/HTTPS webhooks (e.g. OpenClaw / CI / Slack)."""
+
+    ENV_VARS = [
+        "OPENCLAW_WEBHOOK_URL",
+        "MCP_NOTIFICATION_WEBHOOK",
+        "ARTEMIS_WEBHOOK_URL",
+    ]
+
+    @property
+    def name(self) -> str:
+        return "webhook"
+
+    def _get_webhook_url(self) -> str | None:
+        for var in self.ENV_VARS:
+            val = os.getenv(var)
+            if val and val.startswith(("http://", "https://")):
+                return val
+        return None
+
+    def is_available(self) -> bool:
+        return self._get_webhook_url() is not None
+
+    def notify(
+        self,
+        conversation_id: str,
+        message: str,
+        title: str | None = None,
+        event_type: str = "completed",
+        payload: dict[str, Any] | None = None,
+    ) -> bool:
+        url = self._get_webhook_url()
+        if not url:
+            return False
+
+        data = {
+            "event": event_type,
+            "title": title or f"Artemis Task {event_type.capitalize()}",
+            "conversation_id": conversation_id,
+            "message": message,
+            "timestamp": time.time(),
+            "payload": payload or {},
+        }
+
+        try:
+            req_data = json.dumps(data).encode("utf-8")
+            req = urllib.request.Request(
+                url,
+                data=req_data,
+                headers={"Content-Type": "application/json", "User-Agent": "Artemis-MCP/3.0"},
+                method="POST",
+            )
+            with urllib.request.urlopen(req, timeout=5) as response:
+                if response.status in (200, 201, 202, 204):
+                    logger.info(f"Webhook notification delivered to {url}.")
+                    return True
+        except Exception as e:
+            logger.warning(f"Failed to deliver webhook notification to {url}: {e}")
+        return False