[Plugin Arch] Phase 2 — Plugin System Infrastructure

[Al-Pragliola]

Summary

Create the plugin infrastructure in pkg/catalog/plugin/ that allows different catalog types (models, datasets, MCP tools, etc.) to register themselves and be managed by a unified server.

Motivation

With the core primitives from Phase 1 providing generic building blocks, we need a standardized way for catalog implementations to plug in. The plugin system provides a standard interface, a global registry, and config routing — so new catalog types can be added with minimal boilerplate and zero changes to the core.

Scope

• Define the Plugin Interface that every catalog type must implement
• Implement a global plugin registry supporting self-registration via init()
• Define a plugin config structure that routes the correct section of sources.yaml to each plugin
• Define the plugin lifecycle hooks (init, start, stop, health check)

Acceptance Criteria

• pkg/catalog/plugin/ contains the Plugin interface with clearly documented methods
• A global registry allows plugins to register via init() and be discovered at startup
• Config routing correctly maps sources.yaml sections to their respective plugins
• Lifecycle management (init, start, stop) is well-defined and tested
• Unit tests cover registration, config routing, and lifecycle
• make build && make test && make lint pass

Dependencies

• Phase 1 [Plugin Arch] Phase 1 — Extract Core Catalog Primitives into basecatalog #2527

References

• Parent: [Proposal] Plugin-Based Catalog Architecture and catalog-gen tool to generate new catalog types #2220