fix: harden Shell Target recovery and storage

internal/tui/model.go

@@ -283,6 +283,11 @@ func (m Model) mainView() string {
 			fmt.Fprintf(&b, "\n%s\n%s\n", selected.Description.Summary, selected.Evidence)
 		}
 	}
+	for _, item := range m.snapshot.Targets {
+		if !item.Available {
+			fmt.Fprintf(&b, "\nUnavailable %s: %s\n", item.Description.Name, item.AvailabilityEvidence)
+		}
+	}
 	b.WriteString("\nSpace: toggle  ↑/k ↓/j: select  p: manage Proxy Profiles  q/Esc: quit\n")
 	if m.status != "" {
 		fmt.Fprintf(&b, "\n%s\n", m.status)

internal/tui/target_test.go

@@ -32,7 +32,7 @@ func TestTargetPanelShowsOnlyAvailableTargetsAndAppliesAsynchronously(t *testing
 	module.result = app.Result{Snapshot: app.Snapshot{ActiveProfile: "office", Targets: []app.TargetSnapshot{{ID: "shell", Description: target.Description{Name: "Shell", Summary: "Exports for Bash/Zsh"}, Available: true, State: target.Enabled, Evidence: "matches"}}}, Notice: "Shell Target is now Enabled"}
 	model := NewModel(module)
 	view := model.View()
-	if !strings.Contains(view, "Shell") || strings.Contains(view, "APT") || !strings.Contains(view, "Exports for Bash/Zsh") {
+	if !strings.Contains(view, "Shell") || strings.Contains(view, "] APT") || !strings.Contains(view, "Unavailable APT") || !strings.Contains(view, "Exports for Bash/Zsh") {
 		t.Fatalf("Target panel:\n%s", view)
 	}
 
@@ -49,6 +49,16 @@ func TestTargetPanelShowsOnlyAvailableTargetsAndAppliesAsynchronously(t *testing
 	}
 }
 
+func TestUnavailableShellIsOutsideMainListWithDetectionExplanation(t *testing.T) {
+	module := &targetModule{snapshot: app.Snapshot{Targets: []app.TargetSnapshot{
+		{ID: "shell", Description: target.Description{Name: "Shell"}, Available: false, AvailabilityEvidence: "Shell Target requires Bash or Zsh; neither was detected"},
+	}}}
+	view := NewModel(module).View()
+	if strings.Contains(view, "[Disabled ] Shell") || !strings.Contains(view, "Unavailable Shell") || !strings.Contains(view, "requires Bash or Zsh") {
+		t.Fatalf("unavailable Shell explanation:\n%s", view)
+	}
+}
+
 func TestTargetFailurePreservesTruthfulStateAndRendersRedactedError(t *testing.T) {
 	initial := app.Snapshot{ActiveProfile: "office", Targets: []app.TargetSnapshot{{ID: "shell", Description: target.Description{Name: "Shell"}, Available: true, State: target.Enabled}}}
 	module := &targetModule{snapshot: initial, result: app.Result{Snapshot: initial, Err: errors.New("permission denied for alice:REDACTED@proxy")}}