[Plugin Arch] Phase 3 — Unified Catalog Server

[Al-Pragliola]

Summary

Create the unified catalog server entry point that hosts all registered catalog plugins, replacing the previous model-only approach with a server that discovers, initializes, and manages the lifecycle of all registered plugins.

Motivation

Today the catalog server is tightly coupled to the model catalog. With the plugin system in place, the server should be a thin orchestrator: discover registered plugins, initialize them, wire up their HTTP handlers, and manage their lifecycle. This makes the server generic and future-proof.

Scope

• Implement the server entry point that discovers all registered plugins from the registry
• Wire up plugin initialization, HTTP handler registration, and graceful shutdown
• Implement health aggregation across all plugins
• Ensure the server starts with zero plugins gracefully (no crash on empty registry)
• Maintain backward compatibility with existing deployment manifests

Acceptance Criteria

• Server discovers and initializes all registered plugins at startup
• Each plugin's HTTP handlers are mounted under the correct path prefix
• Graceful shutdown stops all plugins cleanly
• Health endpoint aggregates status from all plugins
• Server starts and runs correctly with zero plugins registered
• Existing deployment manifests (Kustomize) continue to work
• make build && make test && make lint pass

Dependencies

• Phase 2 [Plugin Arch] Phase 2 — Plugin System Infrastructure #2528

References

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