feat(v0.5.4): info Session block

Add a Session block to ctask info output, surfacing the workspace
session lease state derived from SessionStatus. Inserted between Path
and any launch-dir fields so the new content is visually distinct
from both blocks.

Format: state on the header line, then indented Mode / Owner / Attach
/ Note rows aligned at column 14. The Owner line omits the hostname
when it matches the local machine. The Attach hint surfaces only for
active+persistent sessions and uses invocationName() so the suggested
command reflects the user's actual invocation. Malformed leases
render as stale with a single-line diagnostic and no Mode/Owner/Attach
rows so we never display fields parsed from a broken file.

Exposes session.CurrentHostname() so the cmd layer has a single
source of truth for the local-vs-remote hostname check.

cmd/info.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/spf13/cobra"
 	"github.com/warrenronsiek/ctask/internal/config"
+	"github.com/warrenronsiek/ctask/internal/session"
 )
 
 var infoCmd = &cobra.Command{
@@ -44,6 +45,8 @@ func runInfo(cmd *cobra.Command, args []string) error {
 	fmt.Printf("Updated:   %s\n", m.UpdatedAt.Local().Format("2006-01-02 15:04:05"))
 	fmt.Printf("Path:      %s\n", ws.Path)
 
+	printSessionBlock(ws.Path, m.Slug)
+
 	if m.LaunchDir != "" {
 		// Per spec amendment: stat the expected path directly instead of
 		// inferring existence from ResolveLaunch's fallback behavior. info
@@ -81,3 +84,60 @@ func runInfo(cmd *cobra.Command, args []string) error {
 
 	return nil
 }
+
+// printSessionBlock renders the v0.5.4 Session block for `ctask info`.
+//
+// Layout (values align at column 14 across the block):
+//
+//	Session:      <state>
+//	  Mode:       <mode>           (omitted when malformed)
+//	  Owner:      [host / ]pid N   (Active; "Last owner:" when stale)
+//	  Attach:     <bin> attach <slug>  (Active + persistent only)
+//	  Note:       <diagnostic>     (stale or malformed only)
+//
+// The hostname is omitted from the Owner/Last-owner line when it matches
+// the local machine, matching the spec's "omit when local" rule.
+//
+// All command-form text uses invocationName() so the hint reflects how
+// the user actually invoked the binary (./ctask vs ctask.exe vs ctask).
+// SessionStatus itself stays neutral and never builds a command string.
+func printSessionBlock(wsPath, slug string) {
+	s := session.SessionStatus(wsPath)
+	fmt.Println()
+
+	switch s.State {
+	case session.SessionStateNone:
+		fmt.Println("Session:      none")
+		return
+	case session.SessionStateStale:
+		// Malformed lease: SessionStatus reports state=stale, mode empty,
+		// diagnostic set. Render only the Note so we don't pretend to
+		// know the mode/owner when the file couldn't be parsed.
+		if s.Diagnostic != "" {
+			fmt.Println("Session:      stale")
+			fmt.Printf("  Note:       %s\n", s.Diagnostic)
+			return
+		}
+	}
+
+	fmt.Printf("Session:      %s\n", s.State)
+	fmt.Printf("  Mode:       %s\n", s.Mode)
+
+	ownerValue := fmt.Sprintf("pid %d", s.PID)
+	if s.Hostname != "" && s.Hostname != session.CurrentHostname() {
+		ownerValue = s.Hostname + " / " + ownerValue
+	}
+	if s.State == session.SessionStateActive {
+		fmt.Printf("  Owner:      %s\n", ownerValue)
+	} else {
+		fmt.Printf("  Last owner: %s\n", ownerValue)
+	}
+
+	if s.State == session.SessionStateActive && s.Mode == "persistent" {
+		fmt.Printf("  Attach:     %s attach %s\n", invocationName(), slug)
+	}
+
+	if s.State == session.SessionStateStale {
+		fmt.Println("  Note:       lease expired; workspace may be available")
+	}
+}