updates to adrs and fixing to reflect go refactor.

decisions/0046-companions-frontend-architecture.md

@@ -14,7 +14,7 @@ How do we build a performant, maintainable frontend that integrates with the NAT
 ## Decision Drivers
 
 * Real-time streaming for chat and voice (WebSocket required)
-* Direct integration with NATS JetStream (binary MessagePack protocol)
+* Direct integration with NATS JetStream (Protocol Buffers encoding, see [ADR-0061](0061-go-handler-refactor.md))
 * Minimal client-side JavaScript (~20KB gzipped target)
 * No frontend build step (no webpack/vite/node required)
 * 3D avatar rendering for immersive experience
@@ -39,8 +39,9 @@ Chosen option: **Option 1 - Go + HTMX + Alpine.js + Three.js**, because it provi
 * No npm, no webpack, no build step — assets served directly
 * Server-side rendering via Go templates
 * WebSocket handled natively in Go (gorilla/websocket)
-* NATS integration with MessagePack in the same binary
+* NATS integration with Protocol Buffers in the same binary
 * Distroless container image for minimal attack surface
+* Type-safe NATS messages via handler-base shared Go module (protobuf stubs)
 
 ### Negative Consequences
 
@@ -58,8 +59,9 @@ Chosen option: **Option 1 - Go + HTMX + Alpine.js + Three.js**, because it provi
 | Client state | Alpine.js 3 | Lightweight reactive UI for local state |
 | 3D Avatars | Three.js + VRM | 3D character rendering with lip-sync |
 | Styling | Tailwind CSS 4 + DaisyUI | Utility-first CSS with component library |
-| Messaging | NATS JetStream | Real-time pub/sub with MessagePack encoding |
+| Messaging | NATS JetStream | Real-time pub/sub with Protocol Buffers encoding |
 | Auth | golang-jwt/jwt/v5 | JWT token handling for OAuth flows |
+| Shared lib | handler-base (Go module) | NATS client, protobuf messages, health, OTel, HTTP clients |
 | Database | PostgreSQL (lib/pq) + SQLite | Persistent + local session storage |
 | Observability | OpenTelemetry SDK | Traces, metrics via OTLP gRPC |
 
@@ -88,7 +90,7 @@ Chosen option: **Option 1 - Go + HTMX + Alpine.js + Three.js**, because it provi
 │              ┌─────────┴─────────┐                              │
 │              │  NATS Client      │                              │
 │              │  (JetStream +     │                              │
-│              │   MessagePack)    │                              │
+│              │   Protobuf)       │                              │
 │              └─────────┬─────────┘                              │
 └────────────────────────┼────────────────────────────────────────┘
                          │
@@ -130,8 +132,9 @@ Chosen option: **Option 1 - Go + HTMX + Alpine.js + Three.js**, because it provi
 ## Links
 
 * Related to [ADR-0003](0003-use-nats-for-messaging.md) (NATS messaging)
-* Related to [ADR-0004](0004-use-messagepack-for-nats.md) (MessagePack encoding)
+* Related to [ADR-0004](0004-use-messagepack-for-nats.md) (MessagePack encoding — superseded by Protocol Buffers, see [ADR-0061](0061-go-handler-refactor.md))
 * Related to [ADR-0011](0011-kuberay-unified-gpu-backend.md) (Ray Serve backend)
 * Related to [ADR-0028](0028-authentik-sso-strategy.md) (OAuth/OIDC)
+* Related to [ADR-0061](0061-go-handler-refactor.md) (Go handler refactor — handler-base shared module, protobuf wire format)
 * [HTMX Documentation](https://htmx.org/docs/)
 * [VRM Specification](https://vrm.dev/en/)