[Feature Request] Add `codex plugins` CLI subcommand for plugin management

Feature Request: Add codex plugins CLI subcommand

Problem

Currently, managing plugins requires using the interactive TUI or manually editing configuration files. There's no convenient way to:

1. List installed plugins from the command line
2. Install/upgrade plugins without entering interactive mode
3. Check plugin status or enable/disable plugins
4. Manage plugin configuration programmatically

Proposed Solution

Add a codex plugins subcommand with the following operations:

# List installed plugins
codex plugins list
codex plugins list --enabled
codex plugins list --disabled

# Install a plugin
codex plugins install <plugin-id>
codex plugins install <plugin-id> --version <version>

# Upgrade plugins
codex plugins upgrade <plugin-id>
codex plugins upgrade --all

# Remove a plugin
codex plugins remove <plugin-id>

# Enable/disable plugins
codex plugins enable <plugin-id>
codex plugins disable <plugin-id>

# Show plugin details
codex plugins show <plugin-id>

# Sync plugins from marketplace
codex plugins sync

Use Cases

1. Setup Script Automation

#!/bin/bash
# setup-codex.sh - One-command environment setup

codex plugins install figma
codex plugins install github
codex plugins install vscode --enable

2. CI/CD Pipeline

# .github/workflows/setup.yml
- name: Setup Codex with required plugins
  run: |
    codex plugins install lint --version 2.0.0
    codex plugins install security-audit
    codex plugins list  # Verify installation

3. Team Environment Consistency

# share-plugins.sh
codex plugins list --json > team-plugins.json

# teammate-setup.sh
codex plugins install-from team-plugins.json

4. Plugin Development Workflow

# Test local plugin
codex plugins install ./my-plugin --dev
codex plugins enable my-plugin
codex plugins logs my-plugin  # View plugin logs

Benefits

1. Automation-friendly - Scripts and CI/CD can manage plugins
2. Team consistency - Easy to share and reproduce plugin setups
3. Faster workflows - No need to enter TUI for simple operations
4. Better discoverability - codex plugins --help shows all capabilities
5. Version control - Plugin configs can be tracked in git

Alternative Considered

• Using TUI for all plugin operations: Too slow for automation
• Manual config file editing: Error-prone and not user-friendly
• Separate codex-plugin CLI tool: Fragmented experience

Additional Context

This would complement the existing plugin marketplace and TUI, providing a complete CLI experience for power users and automation scenarios.

Related: #8512 (Implement Codex Plugins same as Claude Plugins)