Limpar exports deprecated (PluginDiscovery, ComponentRegistry legado)

[MarcosBrendonDePaula]

Problema

• PluginDiscovery em core/plugins/discovery.ts esta @deprecated mas exporta {} as PluginDiscovery (objeto vazio com cast). Ainda re-exportado em core/index.ts.
• ComponentRegistry legado em core/live/ComponentRegistry.ts coexiste com o novo em core/server/live/index.ts. O segundo sobrescreve o primeiro nos re-exports.

Impacto

• Imports do deprecated causam TypeError em runtime
• Conflito de nomes entre dois componentRegistry exports

Solucao

1. Remover export de pluginDiscovery de core/index.ts
2. Remover ou marcar claramente o ComponentRegistry legado
3. Garantir que so existe um componentRegistry export

Esforco Estimado

2-4 horas

[MarcosBrendonDePaula]

Addressed in PR #106.

Changes:

• Removed all 9 deprecated lazy proxy singletons (componentRegistry, liveAuthManager, liveRoomManager, roomEvents, etc.)
• Added registerAuthProvider() as clean replacement
• Migrated all consumers to use liveServer.* directly
• Removed pluginDiscovery singleton and staticPlugin re-exports
• All 609 tests passing