[FEATURE] Allow granular skill enable/disable within plugins to reduce startup overhead

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Problem

Plugins in Claude Code load all skills unconditionally at session startup, regardless of usage patterns. This adds significant startup overhead for users who utilize only a small subset of available skills.

Use Case

Analysis of 158 sessions shows selective skill usage: users employ only 3 skills from the superpowers plugin (~15 skills total), yet the plugin loads all ~8–22k tokens at startup. This results in 4–11% wasted startup cost for unused functionality.

Proposed Solution

Proposed Feature

Add a granular skill enable/disable settings option to allow selective skill loading:

{
  "plugins": {
    "superpowers": {
      "skills": {
        "executing-plans": true,
        "brainstorming": true,
        "writing-plans": true,
        "using-git-worktrees": false,
        "test-driven-development": false
      }
    }
  }
}

### Alternative Solutions


## Proposed Feature

Add a granular skill enable/disable settings option to allow selective skill loading:

```json
{
  "plugins": {
    "superpowers": {
      "skills": {
        "executing-plans": true,
        "brainstorming": true,
        "writing-plans": true,
        "using-git-worktrees": false,
        "test-driven-development": false
      }
    }
  }
}


### Priority

High - Significant impact on productivity

### Feature Category

Performance and speed

### Use Case Example

The issue makes a solid case backed by my actual usage data. It's a legitimate quality-of-life request that would benefit anyone using selective subsets of large plugins.


### Additional Context

_No response_