#3079 fix(mcp): drop broken servers and duplicate mcp plugins

• Bump dotagents to shunkakinoki/dotagents#214 (drops Codex, GitHub, OpenRouter, Paybox, PlanetScale, Sentry, Stripe from .ruler/mcp.json)
• Drop Codex and GitHub from Gemini mcpServers
• Disable context7 and serena plugins; they duplicate the Context7 and Serena MCP servers

🤖 Generated with Claude Code

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Summary by cubic

Removes broken MCP servers and disables plugins that duplicate them.

• Bumps dotagents so Codex, GitHub, OpenRouter, Paybox, PlanetScale, Sentry, and Stripe are dropped from .ruler/mcp.json.
• Removes Codex and GitHub from Gemini's mcpServers.
• Disables the context7 and serena Claude plugins because they duplicate the Context7 and Serena MCP servers.