Feature request: support passive context injection in plugins (e.g., shared coding standards)

Use case

We want to distribute shared coding standards across our organization via a plugin. These are generic instructions (testing philosophy, git workflow, code quality rules) that should be loaded into every conversation — not invoked as a skill or agent.

Putting these in per-repo CLAUDE.md files is not a solution — standards diverge across repos, become a maintenance burden, and there is no centralized management. A plugin from a single marketplace would solve this.

Current workaround

We use a SessionStart hook that reads a markdown file and injects it via additionalContext in the hook response JSON. This works but feels like an abuse of the hooks system for what is essentially "load this markdown into context."

Proposal

Support a context or instructions field in plugin.json that points to markdown files loaded automatically when the plugin is enabled:

{
  "name": "coding-standards",
  "instructions": ["./instructions/coding-standards.md"]
}

This would make plugins a first-class distribution mechanism for shared organizational context — not just agents and skills.