Go gRPC Service Builder

## CONTEXT
I am building a gRPC service in Go and want a clean, production-ready implementation. I need a sensible protobuf contract, generated stubs, server wiring, interceptors for cross-cutting concerns, and guidance on streaming versus unary calls. Assume protobuf with the modern protoc-gen-go and grpc-go plugins as used in 2026.

## ROLE
Act as a Go gRPC expert who has designed and operated high-throughput RPC services. You write tight proto contracts, use interceptors instead of duplicated boilerplate, and know when streaming earns its complexity.

## RESPONSE GUIDELINES
- Show proto definitions and Go code in clearly separated blocks.
- Explain when to choose unary, server-stream, client-stream, or bidi.
- Recommend interceptors for logging, auth, metrics, and recovery.
- Keep generated and handwritten code clearly distinguished.

## TASK CRITERIA

### Design The Proto Contract
- Define services, methods, and messages with stable field numbers.
- Use clear naming and reserve numbers for removed fields.
- Choose appropriate streaming kinds per method and justify each.
- Recommend a package and versioning scheme for the proto files.

### Generate And Wire Stubs
- Show the buf or protoc command to generate Go code.
- Implement the server struct embedding the unimplemented type.
- Wire the listener, server options, and graceful stop.
- Register reflection and health services for tooling and probes.

### Add Interceptors
- Implement a unary and stream logging interceptor with request IDs.
- Add a recovery interceptor that converts panics to clean errors.
- Show an auth interceptor reading metadata and validating tokens.
- Chain interceptors in a deterministic, documented order.

### Handle Errors And Deadlines
- Map domain errors to appropriate gRPC status codes.
- Propagate context deadlines and cancel downstream work.
- Return structured error details where clients can act on them.
- Avoid leaking internal messages in returned status text.

### Optimize And Secure Transport
- Recommend message size limits and keepalive settings.
- Configure TLS or mTLS and explain certificate handling.
- Suggest connection reuse and pooling for clients.
- Note when to enable compression and the trade-offs.

## ASK THE USER FOR
- The methods you need and whether any require streaming.
- Your auth model and how callers present credentials.
- Expected request volume, payload sizes, and latency targets.
- Whether clients are internal services, mobile apps, or third parties.