[FEATURE] Enable overriding plugin settings with configuration in settings.json

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

Some plugins include excellent agents like the plugins/pr-review-toolkit/agents/code-reviewer.md agent.

It's great, but it uses Opus. Sonnet 4.5 is shockingly good compared to Opus 4.1, but Opus 4.1 is very expensive.

I'm already on the Max20 plan _and_ hitting weekly usage limits in a few days just as a result of using sonnet 4.5 effectively with subagents and worktrees. Any unneeded Opus usage is a waste!

But... there's no way to change the model usage of the agent in the plugin without forking the plugin. I don't want to do that, that's an extra thing to track updates for manually... I always want the latest version of the plugin!

Proposed Solution

It would be nice to be able to specify a settingsOverride field in settings.json and be able to specify something for a specific plugin, e.g. "pr-review-toolkit@claude-code-plugins". There are countless ways that you could implement that.

Alternative Solutions

_No response_

Priority

Medium - Would be very helpful

Feature Category

Developer tools/SDK

Use Case Example

Using "pr-review-toolkit@claude-code-plugins" code-reviewer without spending more of Anthropic's money than I have to?

Additional Context

_No response_