feat(contract-validator): add validate_workflow_integration tool (v5.7.1)

Domain Advisory Pattern Hardening - patch release to close gaps from v5.6.0/v5.7.0:

## Added
- New `validate_workflow_integration` MCP tool validates domain plugins expose
  required advisory interfaces (gate command, review command, advisory agent)
- New `MISSING_INTEGRATION` issue type for workflow integration validation
- New `WorkflowIntegrationResult` Pydantic model for structured validation output
- `integrates_with` field on viz-platform and data-platform in marketplace.json
  declaring projman integration metadata
- 4 new test cases for workflow integration validation

## Fixed
- scripts/setup.sh banner version updated from v5.1.0 to v5.7.1

## Documentation
- Updated mcp-tools-reference.md with new tool
- Updated validation-rules.md with Workflow Integration Checks section
- Added /design-gate, /design-review, /data-gate, /data-review to COMMANDS-CHEATSHEET
- Added contract-validator to CONFIGURATION.md plugin table
- Updated README.md Contract Validator tools table

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

mcp-servers/contract-validator/mcp_server/server.py

@@ -131,6 +131,24 @@ class ContractValidatorMCPServer:
                         "required": ["agent_name", "claude_md_path"]
                     }
                 ),
+                Tool(
+                    name="validate_workflow_integration",
+                    description="Validate that a domain plugin exposes the required advisory interfaces (gate command, review command, advisory agent) expected by projman's domain-consultation skill",
+                    inputSchema={
+                        "type": "object",
+                        "properties": {
+                            "plugin_path": {
+                                "type": "string",
+                                "description": "Path to the domain plugin directory"
+                            },
+                            "domain_label": {
+                                "type": "string",
+                                "description": "The Domain/* label it claims to handle, e.g. Domain/Viz"
+                            }
+                        },
+                        "required": ["plugin_path", "domain_label"]
+                    }
+                ),
                 # Report tools (to be implemented in #188)
                 Tool(
                     name="generate_compatibility_report",
@@ -198,6 +216,8 @@ class ContractValidatorMCPServer:
                     result = await self._validate_agent_refs(**arguments)
                 elif name == "validate_data_flow":
                     result = await self._validate_data_flow(**arguments)
+                elif name == "validate_workflow_integration":
+                    result = await self._validate_workflow_integration(**arguments)
                 elif name == "generate_compatibility_report":
                     result = await self._generate_compatibility_report(**arguments)
                 elif name == "list_issues":
@@ -241,6 +261,10 @@ class ContractValidatorMCPServer:
         """Validate agent data flow"""
         return await self.validation_tools.validate_data_flow(agent_name, claude_md_path)
 
+    async def _validate_workflow_integration(self, plugin_path: str, domain_label: str) -> dict:
+        """Validate domain plugin exposes required advisory interfaces"""
+        return await self.validation_tools.validate_workflow_integration(plugin_path, domain_label)
+
     # Report tool implementations (Issue #188)
 
     async def _generate_compatibility_report(self, marketplace_path: str, format: str = "markdown") -> dict: