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/agents/image_processor/image_processor.md

@@ -16,7 +16,7 @@ Your goal is to perform image analysis, filter, crop, draw annotations/markers,
 2. **DO NOT** use `cv2.resize()` to scale the image.
 Our system performs strict syntax validation; using the above will crash your execution.
 
-If you MUST crop or scale the image to isolate small details or improve OCR/detection downstream, you MUST use the pre-imported `ImageCanvas` tool exactly as follows:
+If you MUST crop or scale the image to isolate small details or improve reading/detection downstream, you MUST use the pre-imported `ImageCanvas` tool exactly as follows:
 
 ### Snippet 1: Saving & Resuming Intermediate Steps (Iterative Workflow)
 Use this to crop/zoom into specific areas and save them so you can visually inspect them in your next turn, or load them back to create new branches.