feat(viz-platform): create plugin structure (#177)

- Add plugins/viz-platform/ directory structure
- Create .claude-plugin/plugin.json with metadata
- Create .mcp.json pointing to viz-platform MCP server
- Create hooks/hooks.json with SessionStart hook
- Create symlink to mcp-servers/viz-platform
- Add plugin to marketplace.json

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

plugins/viz-platform/.claude-plugin/plugin.json

@@ -0,0 +1,24 @@
+{
+  "name": "viz-platform",
+  "version": "1.0.0",
+  "description": "Visualization tools with Dash Mantine Components validation, Plotly charts, and theming",
+  "author": {
+    "name": "Leo Miranda",
+    "email": "leobmiranda@gmail.com"
+  },
+  "homepage": "https://gitea.hotserv.cloud/personal-projects/leo-claude-mktplace/src/branch/main/plugins/viz-platform/README.md",
+  "repository": "https://gitea.hotserv.cloud/personal-projects/leo-claude-mktplace.git",
+  "license": "MIT",
+  "keywords": [
+    "dash",
+    "plotly",
+    "mantine",
+    "charts",
+    "dashboards",
+    "theming",
+    "visualization",
+    "dmc"
+  ],
+  "commands": ["./commands/"],
+  "mcpServers": ["./.mcp.json"]
+}