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

artemis/core/diagnostics/schema.py

@@ -0,0 +1,114 @@
+# 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.
+
+"""Schema definitions for Artemis System Diagnostics & Readiness Engine."""
+
+from enum import Enum
+from typing import Any, Literal
+from pydantic import BaseModel, Field
+
+
+class ProbeStatus(str, Enum):
+    """Execution status of a readiness probe."""
+
+    PASS = "pass"  # 🟢 Ready for execution
+    WARN = "warn"  # 🟡 Warning / Non-blocking prerequisite missing (e.g. no devices attached)
+    FAIL = "fail"  # 🔴 Blocking prerequisite failure (e.g. ADB missing, no API key)
+    SKIPPED = "skipped"  # ⚪ Skipped probe
+
+
+class ProbeCategory(str, Enum):
+    """Category of system readiness check."""
+
+    DEVICE = "device"  # Hardware & Device Driver (ADB, Emulator, Cloud device)
+    CREDENTIALS = "auth"  # LLM API Keys & OCR Credentials
+    TOOLCHAIN = "toolchain"  # External tools (FFmpeg, scrcpy, etc.)
+    RUNTIME = "runtime"  # Python runtime & Config health
+
+
+class ProbeAction(BaseModel):
+    """Actionable guidance payload for quick remediation or user guidance."""
+
+    action_type: Literal["command", "hint", "link"] = Field(
+        description="Type of remediation action ('command' to copy/run, 'hint' for guidance, 'link' for docs)"
+    )
+    label: str = Field(description="Display label for the action button or badge")
+    payload: str = Field(description="Command string to execute/copy or explanation hint")
+
+
+class DeviceInfo(BaseModel):
+    """Structured Android device / emulator metadata."""
+
+    serial: str = Field(description="Device serial number or emulator port ID (e.g. emulator-5554)")
+    state: str = Field(
+        default="device", description="Connection state ('device', 'unauthorized', 'offline')"
+    )
+    model: str | None = Field(
+        default=None, description="Device model name (e.g. Pixel 8, sdk_gphone64_arm64)"
+    )
+    product: str | None = Field(default=None, description="Product code name")
+    android_version: str | None = Field(
+        default=None, description="Android OS release version (e.g. 14)"
+    )
+    screen_resolution: str | None = Field(
+        default=None, description="Screen width x height (e.g. 1080x2400)"
+    )
+    is_emulator: bool = Field(default=False, description="Whether the device is an emulator")
+    installed_packages: list[str] = Field(
+        default_factory=list, description="List of recognized installed package names"
+    )
+
+
+class ProbeResult(BaseModel):
+    """Outcome of a single readiness probe check."""
+
+    id: str = Field(
+        description="Unique identifier for the probe (e.g. 'android_adb', 'gemini_api_key')"
+    )
+    category: ProbeCategory = Field(description="Category of the probe")
+    title: str = Field(description="Human-readable title (e.g. 'Device / Emulator Connected')")
+    status: ProbeStatus = Field(description="Current status (pass, warn, fail)")
+    is_blocker: bool = Field(
+        default=True, description="Whether passing this probe is strictly required to run tasks"
+    )
+    summary: str = Field(
+        description="Short badge summary text (e.g. 'Connected', 'No Device', 'Active & Ready')"
+    )
+    description: str = Field(description="Detailed explanation of the status")
+    metadata: dict[str, Any] = Field(
+        default_factory=dict, description="Arbitrary extra metadata (e.g. device list)"
+    )
+    actions: list[ProbeAction] = Field(
+        default_factory=list, description="List of actionable remediation steps"
+    )
+
+
+class SystemReadinessReport(BaseModel):
+    """Aggregated system readiness report across all probes."""
+
+    overall_ready: bool = Field(description="True if all blocker probes are passing")
+    blocker_count: int = Field(description="Total count of required blocker probes")
+    passed_blocker_count: int = Field(
+        description="Count of required blocker probes currently passing"
+    )
+    probes: list[ProbeResult] = Field(
+        default_factory=list, description="Ordered list of probe results"
+    )
+    active_device: DeviceInfo | None = Field(
+        default=None, description="Currently selected/active target device"
+    )
+    os_type: str = Field(
+        default="linux", description="Operating system type ('linux', 'darwin', 'windows')"
+    )
+    timestamp: float = Field(description="Unix timestamp of when the report was generated")