Plugin dependency resolution

When Plugin B depends on Plugin A but the host loads plugins alphabetically or in undefined order, Plugin B crashes with a cryptic error whenever its load happens to precede Plugin A's. ISO 25010 maintainability.modularity requires that inter-component dependencies be explicit and resolvable; implicit alphabetical load order is the opposite of this. The failure is also non-deterministic across environments — it may work in development (where plugin directories happen to be in the right order) and fail in production after a deploy changes the filesystem state.

Support a dependencies field in plugin manifests and topologically sort the load order before initializing any plugin. Circular dependencies should produce an explicit error at startup, not a runtime crash.

function resolveLoadOrder(plugins: PluginManifest[]): PluginManifest[] {
  const graph = new Map<string, string[]>();
  for (const p of plugins) {
    graph.set(p.name, Object.keys(p.dependencies ?? {}));
  }
  return topologicalSort(graph); // throws on cycles
}