Function enable_plugin

src/agents/claude.rs:554–563

Merge `enabledPlugins.tracedecay@tracedecay = true` into settings, preserving existing keys. Idempotent.

(settings: &mut serde_json::Value)

/// Merge `enabledPlugins.tracedecay@tracedecay = true` into settings,
/// preserving existing keys. Idempotent.
fn enable_plugin(settings: &mut serde_json::Value) {
    // `Value`'s `IndexMut<&str>` panics if the parent is a non-object,
    // non-null value (e.g. a user `settings.json` with `"enabledPlugins": "x"`).
    // Coerce it to an object first, mirroring the `register_marketplace` guard.
    if !settings["enabledPlugins"].is_object() && !settings["enabledPlugins"].is_null() {
        settings["enabledPlugins"] = json!({});
    }
    settings["enabledPlugins"][PLUGIN_IDENTIFIER] = json!(true);
    eprintln!("\x1b[32m✔\x1b[0m Enabled plugin {PLUGIN_IDENTIFIER}");
}

/// Remove the `enabledPlugins.tracedecay@tracedecay` entry (idempotent).
/// Returns true if modified.