feat: add server layer with HTTP and gRPC transport

Create internal/server package with HTTP and gRPC server constructors
using Kratos transport layer. Includes Wire provider set for DI,
recovery/tracing/logging middleware, and graceful nil-safe config handling.

Fix .gitignore 'server' pattern to only match root-level binary.

.gitignore

@@ -5,7 +5,7 @@
 *.so
 *.dylib
 file-service
-server
+/server
 bin/
 
 # Test binary, built with `go test -c`

internal/server/grpc.go

@@ -0,0 +1,34 @@
+package server
+
+import (
+	pb "rag/file-system/api/file/v1"
+	"rag/file-system/internal/conf"
+	"rag/file-system/internal/service"
+
+	"github.com/go-kratos/kratos/v2/log"
+	"github.com/go-kratos/kratos/v2/middleware/logging"
+	"github.com/go-kratos/kratos/v2/middleware/recovery"
+	"github.com/go-kratos/kratos/v2/middleware/tracing"
+	"github.com/go-kratos/kratos/v2/transport/grpc"
+)
+
+func NewGRPCServer(c *conf.Server, svc *service.FileService, logger log.Logger) *grpc.Server {
+	opts := []grpc.ServerOption{
+		grpc.Middleware(
+			recovery.Recovery(),
+			tracing.Server(),
+			logging.Server(logger),
+		),
+	}
+	if c != nil && c.Grpc != nil {
+		if c.Grpc.Addr != "" {
+			opts = append(opts, grpc.Address(c.Grpc.Addr))
+		}
+		if c.Grpc.Timeout != nil {
+			opts = append(opts, grpc.Timeout(c.Grpc.Timeout.AsDuration()))
+		}
+	}
+	srv := grpc.NewServer(opts...)
+	pb.RegisterFileServiceServer(srv, svc)
+	return srv
+}

internal/server/http.go

@@ -0,0 +1,34 @@
+package server
+
+import (
+	pb "rag/file-system/api/file/v1"
+	"rag/file-system/internal/conf"
+	"rag/file-system/internal/service"
+
+	"github.com/go-kratos/kratos/v2/log"
+	"github.com/go-kratos/kratos/v2/middleware/logging"
+	"github.com/go-kratos/kratos/v2/middleware/recovery"
+	"github.com/go-kratos/kratos/v2/middleware/tracing"
+	"github.com/go-kratos/kratos/v2/transport/http"
+)
+
+func NewHTTPServer(c *conf.Server, svc *service.FileService, logger log.Logger) *http.Server {
+	opts := []http.ServerOption{
+		http.Middleware(
+			recovery.Recovery(),
+			tracing.Server(),
+			logging.Server(logger),
+		),
+	}
+	if c != nil && c.Http != nil {
+		if c.Http.Addr != "" {
+			opts = append(opts, http.Address(c.Http.Addr))
+		}
+		if c.Http.Timeout != nil {
+			opts = append(opts, http.Timeout(c.Http.Timeout.AsDuration()))
+		}
+	}
+	srv := http.NewServer(opts...)
+	pb.RegisterFileServiceHTTPServer(srv, svc)
+	return srv
+}

internal/server/server.go

@@ -0,0 +1,8 @@
+package server
+
+import "github.com/google/wire"
+
+var ProviderSet = wire.NewSet(
+	NewHTTPServer,
+	NewGRPCServer,
+)