Add protocol_version field to Initialize RPC for forward compatibility as the plugin protocol evolves.
Changes:
- Add protocol_version to InitializeRequest (server → plugin)
- Add protocol_version to InitializeResponse (plugin → server)
- Set current protocol version to 1
- Version 0 indicates pre-versioning implementations (treated as v1)
This allows the server and plugins to negotiate capabilities:
- Server can avoid calling RPCs that older plugins don't implement
- Plugins can detect newer servers and enable advanced features
- Graceful degradation when versions mismatch
The AI service now reports protocol version 1 during initialization.
Add gRPC-based plugin protocol implementation to the AI sidecar, enabling the GitCaddy server to manage it as an external plugin with lifecycle control and health monitoring.
Plugin Protocol Implementation:
- Add plugin.proto with PluginService definition (Initialize, Shutdown, HealthCheck, GetManifest, OnEvent, HandleHTTP)
- Implement PluginServiceImpl gRPC service in C#
- Return manifest declaring AI service capabilities, routes, and required permissions
- Integrate license validation into health checks
- Register plugin service alongside existing AI service
Server Integration:
- Configure Kestrel for HTTP/1.1 + HTTP/2 on port 5000 (enables gRPC + REST)
- Map PluginService gRPC endpoint at /plugin.v1.PluginService
- Enable server to call Initialize on startup, HealthCheck periodically, and Shutdown on graceful stop
This completes Phase 5 of the AI integration, allowing the server's external plugin manager to monitor and control the sidecar's lifecycle instead of relying on manual process management.
