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>

plugins/contract-validator/.claude-plugin/plugin.json

@@ -0,0 +1,22 @@
+{
+  "name": "contract-validator",
+  "version": "1.0.0",
+  "description": "Cross-plugin compatibility validation and Claude.md agent verification",
+  "author": {
+    "name": "Leo Miranda",
+    "email": "leobmiranda@gmail.com"
+  },
+  "homepage": "https://gitea.hotserv.cloud/personal-projects/leo-claude-mktplace/src/branch/main/plugins/contract-validator/README.md",
+  "repository": "https://gitea.hotserv.cloud/personal-projects/leo-claude-mktplace.git",
+  "license": "MIT",
+  "keywords": [
+    "validation",
+    "contracts",
+    "compatibility",
+    "agents",
+    "interfaces",
+    "cross-plugin"
+  ],
+  "commands": ["./commands/"],
+  "mcpServers": ["./.mcp.json"]
+}