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

apps/showcase_ui/src/app/utils/action-formatter.util.spec.ts

@@ -0,0 +1,112 @@
+import {
+  getStepPreImageUrl,
+  getStepPostImageUrl
+} from './action-formatter.util';
+
+describe('action-formatter.util screenshot chaining', () => {
+  it('should chain pre/post images correctly in FailureAnalyzer multi-step recovery', () => {
+    const stepData = {
+      step_id: 'step-06',
+      pre_image_name: '01a0e8d8cddbeb6a352e3bef1afbee0f0476a05b0fc62abb78e59c7b6aa16079',
+      post_image_name: '484361b1ab4b340415e01042e3496f0edc0549c837c897ece242835d12d7d71d',
+      action_taken: {
+        action: 'tap',
+        coordinates: [540, 720],
+        timestamp: 1787077538.0
+      },
+      last_execution_result: {
+        status: 'success',
+        repair_status: 'fixed',
+        execution: [
+          {
+            attempts: ['Pre-execution validation failed']
+          }
+        ]
+      },
+      generic_tools: [
+        {
+          trace_id: 'tool-save-note',
+          name: 'save_note',
+          type: 'tool',
+          timestamp: 1787077537.0,
+          payload: { args: { title: 'Note 1' } }
+        },
+        {
+          trace_id: 'agent-failure-analyzer',
+          name: 'failure_analyzer',
+          agent_name: 'failure_analyzer',
+          type: 'agent',
+          timestamp: 1787077540.0,
+          payload: {
+            args: {
+              pre_screenshot_name: '01a0e8d8cddbeb6a352e3bef1afbee0f0476a05b0fc62abb78e59c7b6aa16079',
+              post_screenshot_name: 'fbdf17fa7a970d2c37aa52ae4336119e76a7d13ea457811cf8aaab19b3f53843'
+            }
+          }
+        },
+        {
+          trace_id: 'action-click-1',
+          name: 'click',
+          type: 'action',
+          agent_name: 'failure_analyzer',
+          timestamp: 1787077607.0,
+          payload: {
+            args: { target: '[500, 300]' },
+            result: {
+              outcome: 'Clicked successfully',
+              post_image_name: '18bd2ac49e64976f1e74e828ddae76e54da1587044b1d3fb01317dd202ff7c67'
+            }
+          }
+        },
+        {
+          trace_id: 'action-click-seq-2',
+          name: 'click_sequence',
+          type: 'action',
+          agent_name: 'failure_analyzer',
+          timestamp: 1787077631.0,
+          payload: {
+            args: { sequence: '[[500, 300], [876, 360]]' },
+            result: {
+              outcome: 'Sequence clicked successfully',
+              post_image_name: '484361b1ab4b340415e01042e3496f0edc0549c837c897ece242835d12d7d71d'
+            }
+          }
+        }
+      ]
+    };
+
+    const action1 = stepData.generic_tools[2]; // click
+    const action2 = stepData.generic_tools[3]; // click_sequence
+
+    // Action 1: Pre should be the failed state screenshot (fbdf17fa...), Post should be Action 1's post (18bd2ac4...)
+    const act1Pre = getStepPreImageUrl(stepData, action1);
+    const act1Post = getStepPostImageUrl(stepData, action1);
+    expect(act1Pre).toBe('/images/fbdf17fa7a970d2c37aa52ae4336119e76a7d13ea457811cf8aaab19b3f53843');
+    expect(act1Post).toBe('/images/18bd2ac49e64976f1e74e828ddae76e54da1587044b1d3fb01317dd202ff7c67');
+
+    // Action 2: "下一次的决策前是上一次的动作后" -> Pre MUST be Action 1's post (18bd2ac4...), Post should be Action 2's post (484361b1...)
+    const act2Pre = getStepPreImageUrl(stepData, action2);
+    const act2Post = getStepPostImageUrl(stepData, action2);
+    expect(act2Pre).toBe('/images/18bd2ac49e64976f1e74e828ddae76e54da1587044b1d3fb01317dd202ff7c67');
+    expect(act2Post).toBe('/images/484361b1ab4b340415e01042e3496f0edc0549c837c897ece242835d12d7d71d');
+  });
+
+  it('should handle standard single-action step correctly', () => {
+    const stepData = {
+      step_id: 'step-01',
+      pre_image_name: 'pre123',
+      post_image_name: 'post456',
+      action_taken: {
+        action: 'tap',
+        coordinates: [100, 200],
+        timestamp: 1000
+      }
+    };
+
+    const preUrl = getStepPreImageUrl(stepData, stepData.action_taken);
+    const postUrl = getStepPostImageUrl(stepData, stepData.action_taken);
+
+    expect(preUrl).toBe('/images/pre123');
+    expect(postUrl).toBe('/images/post456');
+  });
+});