feat: Add Codex CLI plugin manifest

[internet-dot]

Adds a Codex CLI plugin manifest.

What this adds: .codex-plugin/plugin.json, .mcp.json, skills/SKILL.md

Related: awesome-codex-plugins | codex-plugin-scanner

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[gemini-code-assist]

Code Review

This pull request introduces the initial configuration for the GenAI Toolbox Codex plugin, including the plugin manifest, MCP server configuration, and skill documentation. Feedback suggests adding the -y flag to the npx command in .mcp.json to ensure non-interactive execution. Additionally, several updates are recommended to align the plugin's display name and documentation with the project's rebranding to 'MCP Toolbox for Databases' for consistency.

[gemini-code-assist]

Consider adding the -y flag to the npx command. This ensures that npx runs non-interactively and automatically accepts the installation of the @toolbox-sdk/server package if it's not already present in the environment. This is a best practice for plugin manifests to avoid hanging in non-interactive shells, and it is consistent with the examples provided in the project's README (line 82).

      "args": [
        "-y",
        "@toolbox-sdk/server",
        "--config",
        "tools.yaml"
      ]

[gemini-code-assist]

The displayName should be updated to "MCP Toolbox for Databases" to align with the project's rebranding mentioned in the README (line 36). Other fields like longDescription already use the updated name.

Suggested change

	"displayName": "GenAI Toolbox",
	"displayName": "MCP Toolbox for Databases",

[gemini-code-assist]

Update the skill title and description to use "MCP Toolbox" instead of "GenAI Toolbox" for consistency with the current project branding and the rest of the documentation.

Suggested change

	# GenAI Toolbox for Codex
	Use GenAI Toolbox from Codex via MCP.
	## When to use
	- When you need genai-toolbox capabilities in your Codex workflow
	# MCP Toolbox for Codex
	Use MCP Toolbox from Codex via MCP.
	## When to use
	- When you need MCP Toolbox capabilities in your Codex workflow