feat(contract-validator): create plugin structure (#185)

Create the basic plugin structure for contract-validator:

Plugin structure:
- plugins/contract-validator/.claude-plugin/plugin.json
- plugins/contract-validator/.mcp.json
- plugins/contract-validator/mcp-servers/contract-validator -> symlink

MCP server scaffolding:
- mcp-servers/contract-validator/mcp_server/server.py (7 placeholder tools)
- mcp-servers/contract-validator/pyproject.toml
- mcp-servers/contract-validator/requirements.txt
- Virtual environment with mcp>=0.9.0

Tools defined (placeholders):
- parse_plugin_interface
- parse_claude_md_agents
- validate_compatibility
- validate_agent_refs
- validate_data_flow
- generate_compatibility_report
- list_issues

Sprint: Sprint 2 - contract-validator Plugin

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

mcp-servers/contract-validator/pyproject.toml

@@ -0,0 +1,41 @@
+[build-system]
+requires = ["setuptools>=61.0", "wheel"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "contract-validator-mcp"
+version = "1.0.0"
+description = "MCP Server for cross-plugin compatibility validation and agent verification"
+readme = "README.md"
+license = {text = "MIT"}
+requires-python = ">=3.10"
+authors = [
+    {name = "Leo Miranda"}
+]
+classifiers = [
+    "Development Status :: 4 - Beta",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: MIT License",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+]
+dependencies = [
+    "mcp>=0.9.0",
+    "pydantic>=2.5.0",
+]
+
+[project.optional-dependencies]
+dev = [
+    "pytest>=7.4.3",
+    "pytest-asyncio>=0.23.0",
+]
+
+[tool.setuptools.packages.find]
+where = ["."]
+include = ["mcp_server*"]
+
+[tool.pytest.ini_options]
+asyncio_mode = "auto"
+testpaths = ["tests"]