Fix Docker build by adding protobuf code generation step

The Docker build was failing because protobuf-generated code wasn't
  available during compilation. Changes made:
  - Added protoc and protobuf-dev packages to build dependencies
  - Installed protoc-gen-go and protoc-gen-go-grpc plugins
  - Added make proto-gen step to generate pb files before build

  🤖 Generated with [Claude Code](https://claude.com/claude-code)

  Co-Authored-By: Claude <noreply@anthropic.com>

Dockerfile

@@ -6,8 +6,8 @@ ARG VERSION=dev
 ARG GIT_COMMIT=unknown
 ARG BUILD_TIME=unknown
 
-# Install build dependencies
+# Install build dependencies including protoc
-RUN apk add --no-cache git make
+RUN apk add --no-cache git make protobuf protobuf-dev
 
 # Set working directory
 WORKDIR /build
@@ -18,9 +18,16 @@ COPY go.mod go.sum ./
 # Download dependencies
 RUN go mod download
 
+# Install protoc plugins
+RUN go install google.golang.org/protobuf/cmd/protoc-gen-go@latest && \
+    go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@latest
+
 # Copy source code
 COPY . .
 
+# Generate protobuf code
+RUN make proto-gen
+
 # Build binary with version information
 RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo \
     -ldflags "-X main.Version=${VERSION} -X main.GitCommit=${GIT_COMMIT} -X main.BuildTime=${BUILD_TIME}" \