Add Phase 3 CLI tools: exo client and exod server binaries

- exod: gRPC daemon with auto-migration, graceful shutdown (SIGINT/SIGTERM),
  configurable listen address and data directory via flags
- exo: CLI client with import (YAML artifacts), tag add/list, cat add/list,
  search by tag commands; connects via EXO_ADDR env var
- Add bin/ to .gitignore

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cmd/exod/main.go

@@ -0,0 +1,88 @@
+// Command exod is the gRPC backend daemon for the exo system.
+// It is the sole owner of the SQLite database and blob store.
+package main
+
+import (
+	"flag"
+	"log"
+	"net"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"google.golang.org/grpc"
+
+	"git.wntrmute.dev/kyle/exo/blob"
+	"git.wntrmute.dev/kyle/exo/config"
+	"git.wntrmute.dev/kyle/exo/db"
+	pb "git.wntrmute.dev/kyle/exo/proto/exo/v1"
+	"git.wntrmute.dev/kyle/exo/server"
+)
+
+var version = "dev"
+
+func main() {
+	var (
+		listenAddr = flag.String("listen", "", "gRPC listen address (default from config)")
+		basePath   = flag.String("base", "", "base data directory (default $HOME/exo)")
+		showVer    = flag.Bool("version", false, "print version and exit")
+	)
+	flag.Parse()
+
+	if *showVer {
+		log.Printf("exod %s", version)
+		os.Exit(0)
+	}
+
+	cfg := config.Default()
+	if *basePath != "" {
+		cfg = config.FromBasePath(*basePath)
+	}
+	if *listenAddr != "" {
+		cfg.GRPCListenAddr = *listenAddr
+	}
+
+	// Ensure data directories exist.
+	if err := os.MkdirAll(cfg.BasePath, 0o750); err != nil {
+		log.Fatalf("exod: failed to create base directory: %v", err)
+	}
+	if err := os.MkdirAll(cfg.BlobStorePath, 0o750); err != nil {
+		log.Fatalf("exod: failed to create blob store directory: %v", err)
+	}
+
+	// Open and migrate the database.
+	database, err := db.Open(cfg.DatabasePath)
+	if err != nil {
+		log.Fatalf("exod: failed to open database: %v", err)
+	}
+	defer func() { _ = database.Close() }()
+
+	if err := db.Migrate(database); err != nil {
+		log.Fatalf("exod: failed to migrate database: %v", err)
+	}
+
+	blobStore := blob.NewStore(cfg.BlobStorePath)
+
+	// Start gRPC server.
+	lis, err := net.Listen("tcp", cfg.GRPCListenAddr)
+	if err != nil {
+		log.Fatalf("exod: failed to listen on %s: %v", cfg.GRPCListenAddr, err)
+	}
+
+	grpcServer := grpc.NewServer()
+	pb.RegisterArtifactServiceServer(grpcServer, server.NewArtifactServer(database, blobStore))
+
+	// Graceful shutdown on SIGINT/SIGTERM.
+	sigCh := make(chan os.Signal, 1)
+	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
+	go func() {
+		sig := <-sigCh
+		log.Printf("exod: received %s, shutting down", sig)
+		grpcServer.GracefulStop()
+	}()
+
+	log.Printf("exod %s listening on %s", version, cfg.GRPCListenAddr)
+	if err := grpcServer.Serve(lis); err != nil {
+		log.Fatalf("exod: gRPC server error: %v", err)
+	}
+}