Add mcp logs command for streaming container logs

New server-streaming Logs RPC streams container output to the CLI.
Supports --tail/-n, --follow/-f, --timestamps/-t, --since.

Detects journald log driver and falls back to journalctl (podman logs
can't read journald outside the originating user session). New containers
default to k8s-file via mcp user's containers.conf.

Also adds stream auth interceptor for the agent gRPC server (required
for streaming RPCs).

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

cmd/mcp/logs.go

@@ -0,0 +1,81 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/spf13/cobra"
+
+	mcpv1 "git.wntrmute.dev/mc/mcp/gen/mcp/v1"
+	"git.wntrmute.dev/mc/mcp/internal/config"
+)
+
+func logsCmd() *cobra.Command {
+	var (
+		tail       int
+		follow     bool
+		timestamps bool
+		since      string
+	)
+
+	cmd := &cobra.Command{
+		Use:   "logs <service>[/<component>]",
+		Short: "Show container logs",
+		Args:  cobra.ExactArgs(1),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			cfg, err := config.LoadCLIConfig(cfgPath)
+			if err != nil {
+				return fmt.Errorf("load config: %w", err)
+			}
+
+			serviceName, component := parseServiceArg(args[0])
+
+			def, err := loadServiceDef(cmd, cfg, serviceName)
+			if err != nil {
+				return err
+			}
+
+			address, err := findNodeAddress(cfg, def.Node)
+			if err != nil {
+				return err
+			}
+
+			client, conn, err := dialAgent(address, cfg)
+			if err != nil {
+				return fmt.Errorf("dial agent: %w", err)
+			}
+			defer func() { _ = conn.Close() }()
+
+			stream, err := client.Logs(cmd.Context(), &mcpv1.LogsRequest{
+				Service:    serviceName,
+				Component:  component,
+				Tail:       int32(tail),
+				Follow:     follow,
+				Timestamps: timestamps,
+				Since:      since,
+			})
+			if err != nil {
+				return fmt.Errorf("logs: %w", err)
+			}
+
+			for {
+				resp, err := stream.Recv()
+				if err == io.EOF {
+					return nil
+				}
+				if err != nil {
+					return fmt.Errorf("recv: %w", err)
+				}
+				_, _ = os.Stdout.Write(resp.Data)
+			}
+		},
+	}
+
+	cmd.Flags().IntVarP(&tail, "tail", "n", 0, "number of lines from end (0 = all)")
+	cmd.Flags().BoolVarP(&follow, "follow", "f", false, "follow log output")
+	cmd.Flags().BoolVarP(&timestamps, "timestamps", "t", false, "show timestamps")
+	cmd.Flags().StringVar(&since, "since", "", "show logs since (e.g., 2h, 2026-03-28T00:00:00Z)")
+
+	return cmd
+}