9c move Non-IO grouping policy from core stats/types into dashboard

Snapshot.NonIOFamilies, Snapshot.NonIOFamiliesCount, and
types.IsNonIOSyscallFamily encoded a TUI tab concept in core packages.
Move this filtering into internal/tui/dashboard/nonio.go as unexported
helpers so the dashboard owns its own grouping policy and
Snapshot.Families remains the neutral core API.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

3 files changed, 74 insertions, 2 deletions

diff --git a/internal/tui/dashboard/model.go b/internal/tui/dashboard/model.go
index 1f479c7..fa36453 100644
--- a/internal/tui/dashboard/model.go
+++ b/internal/tui/dashboard/model.go
@@ -884,7 +884,7 @@ func (m Model) maxSyscallsRows() int {
 }
 
 func (m Model) maxNonIORows() int {
-	return m.snapshotOrZero().NonIOFamiliesCount()
+	return nonIOFamiliesCount(m.snapshotOrZero().Families())
 }
 
 func (m Model) maxFilesRows() int {
diff --git a/internal/tui/dashboard/nonio.go b/internal/tui/dashboard/nonio.go
index aef63f4..42069a2 100644
--- a/internal/tui/dashboard/nonio.go
+++ b/internal/tui/dashboard/nonio.go
@@ -6,6 +6,7 @@ import (
 
 	"ior/internal/statsengine"
 	common "ior/internal/tui/common"
+	"ior/internal/types"
 )
 
 func renderNonIO(snap *statsengine.Snapshot, width, height int) string {
@@ -17,7 +18,7 @@ func renderNonIOWithOffset(snap *statsengine.Snapshot, width, height, offset, se
 		return "Non-IO: waiting for stats..."
 	}
 
-	rowsData := snap.NonIOFamilies()
+	rowsData := nonIOFamilies(snap.Families())
 	columns, rows := nonIOTableData(rowsData, width)
 	if len(rows) == 0 {
 		return "Non-IO: no data"
@@ -97,3 +98,37 @@ func nonIORowsCompact(families []statsengine.FamilySnapshot) [][]string {
 	}
 	return rows
 }
+
+// isFileSyscallFamily reports whether family belongs to file-system/fd views.
+// This is a dashboard presentation concept: the Non-IO tab excludes FS families.
+func isFileSyscallFamily(family types.SyscallFamily) bool {
+	return family == types.FamilyFS
+}
+
+// isNonIOSyscallFamily reports whether family should appear in the Non-IO tab.
+// This is a dashboard grouping policy kept out of the core stats/types packages.
+func isNonIOSyscallFamily(family types.SyscallFamily) bool {
+	return family != "" && !isFileSyscallFamily(family)
+}
+
+// nonIOFamilies filters family snapshot rows to those outside the FS family.
+func nonIOFamilies(all []statsengine.FamilySnapshot) []statsengine.FamilySnapshot {
+	rows := make([]statsengine.FamilySnapshot, 0, len(all))
+	for _, row := range all {
+		if isNonIOSyscallFamily(row.Family) {
+			rows = append(rows, row)
+		}
+	}
+	return rows
+}
+
+// nonIOFamiliesCount returns the number of non-FS family rows.
+func nonIOFamiliesCount(all []statsengine.FamilySnapshot) int {
+	count := 0
+	for _, row := range all {
+		if isNonIOSyscallFamily(row.Family) {
+			count++
+		}
+	}
+	return count
+}
diff --git a/internal/tui/dashboard/nonio_test.go b/internal/tui/dashboard/nonio_test.go
index 5fabc76..0b5fc25 100644
--- a/internal/tui/dashboard/nonio_test.go
+++ b/internal/tui/dashboard/nonio_test.go
@@ -35,3 +35,40 @@ func TestRenderNonIOIncludesExpectedFamilyRows(t *testing.T) {
 		t.Fatalf("non-io table should exclude FS rows:\n%s", out)
 	}
 }
+
+func TestNonIOFamiliesFiltering(t *testing.T) {
+	all := []statsengine.FamilySnapshot{
+		{Family: types.FamilyFS, Name: "FS"},
+		{Family: types.FamilyPolling, Name: "Polling"},
+		{Family: types.FamilyProcess, Name: "Process"},
+	}
+
+	rows := nonIOFamilies(all)
+	if len(rows) != 2 {
+		t.Fatalf("nonIOFamilies len = %d, want 2", len(rows))
+	}
+	if rows[0].Family == types.FamilyFS || rows[1].Family == types.FamilyFS {
+		t.Fatalf("nonIOFamilies included FS: %+v", rows)
+	}
+	if got := nonIOFamiliesCount(all); got != 2 {
+		t.Fatalf("nonIOFamiliesCount = %d, want 2", got)
+	}
+}
+
+func TestIsNonIOSyscallFamily(t *testing.T) {
+	tests := []struct {
+		family types.SyscallFamily
+		want   bool
+	}{
+		{types.FamilyFS, false},
+		{types.FamilyPolling, true},
+		{types.FamilyProcess, true},
+		{types.FamilyNetwork, true},
+		{"", false},
+	}
+	for _, tt := range tests {
+		if got := isNonIOSyscallFamily(tt.family); got != tt.want {
+			t.Errorf("isNonIOSyscallFamily(%q) = %v, want %v", tt.family, got, tt.want)
+		}
+	}
+}