Trim whitespace from token file in CLI

Token files with trailing newlines caused gRPC "non-printable ASCII
characters" errors in the authorization header.

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

cmd/mcp/dial.go

@@ -6,6 +6,7 @@ import (
 	"crypto/x509"
 	"fmt"
 	"os"
+	"strings"
 
 	mcpv1 "git.wntrmute.dev/kyle/mcp/gen/mcp/v1"
 	"git.wntrmute.dev/kyle/mcp/internal/config"
@@ -68,5 +69,5 @@ func loadBearerToken(cfg *config.CLIConfig) (string, error) {
 	if err != nil {
 		return "", fmt.Errorf("read token from %q: %w (run 'mcp login' first)", cfg.Auth.TokenPath, err)
 	}
-	return string(token), nil
+	return strings.TrimSpace(string(token)), nil
 }