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/integration/test_artemis_login.py

@@ -0,0 +1,81 @@
+# 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.
+
+import os
+import pty
+import select
+import sys
+import time
+import pytest
+
+
+@pytest.mark.skip(reason="Manual integration test requiring remote host")
+def test_artemis_ssh_login():
+    """Manual test to verify SSH login to remote Artemis instance."""
+    run_artemis_ssh_login()
+
+
+def run_artemis_ssh_login():
+    host = os.getenv("ARTEMIS_SSH_TEST_HOST", "127.0.0.1")
+    user = os.getenv("ARTEMIS_SSH_TEST_USER", "artemis")
+    password = os.getenv("ARTEMIS_SSH_TEST_PASSWORD", "password")
+
+    cmd = [
+        "ssh",
+        "-o",
+        "StrictHostKeyChecking=no",
+        "-o",
+        "UserKnownHostsFile=/dev/null",
+        "-o",
+        "PreferredAuthentications=password,keyboard-interactive",
+        f"{user}@{host}",
+        (
+            "echo '=================================================='; echo '🚀 BINGO!! PURE"
+            " PASSWORD LOGIN VICTORY 🚀'; echo"
+            " '=================================================='; whoami; hostname; uptime"
+        ),
+    ]
+
+    master, slave = pty.openpty()
+    pid = os.fork()
+    if pid == 0:
+        os.close(master)
+        os.execvp(cmd[0], cmd)
+    else:
+        os.close(slave)
+        output = b""
+        start = time.time()
+        password_sent = False
+        while time.time() - start < 15:
+            r, _, _ = select.select([master], [], [], 0.3)
+            if master in r:
+                try:
+                    data = os.read(master, 2048)
+                    if not data:
+                        break
+                    output += data
+                    sys.stdout.buffer.write(data)
+                    sys.stdout.flush()
+                    if (b"Password:" in data or b"password:" in data) and not password_sent:
+                        time.sleep(0.2)
+                        os.write(master, f"{password}\n".encode())
+                        password_sent = True
+                except OSError:
+                    break
+        os.close(master)
+        os.waitpid(pid, 0)
+
+
+if __name__ == "__main__":
+    run_artemis_ssh_login()