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, 6 insertions, 56 deletions

diff --git a/internal/statsengine/engine_test.go b/internal/statsengine/engine_test.go
index 0500d20..6eb19e8 100644
--- a/internal/statsengine/engine_test.go
+++ b/internal/statsengine/engine_test.go
@@ -115,12 +115,13 @@ func TestEngineAggregatesSyscallFamilies(t *testing.T) {
 		t.Fatalf("FS family = %+v, want count=1 bytes=4", families["FS"])
 	}
 
-	nonIO := familyRowsByName(snap.NonIOFamilies())
-	if _, ok := nonIO["FS"]; ok {
-		t.Fatalf("NonIOFamilies should not include FS: %+v", nonIO["FS"])
+	// Verify that non-FS families exist and FS is present in the full
+	// family list — Non-IO filtering has moved to the dashboard package.
+	if _, ok := families["Polling"]; !ok {
+		t.Fatalf("Families missing Polling row: %+v", families)
 	}
-	if nonIO["Polling"].Count != 2 || nonIO["Process"].Count != 1 {
-		t.Fatalf("NonIOFamilies missing expected rows: %+v", nonIO)
+	if _, ok := families["Process"]; !ok {
+		t.Fatalf("Families missing Process row: %+v", families)
 	}
 }
 
diff --git a/internal/statsengine/snapshot.go b/internal/statsengine/snapshot.go
index bec92fb..fa9c948 100644
--- a/internal/statsengine/snapshot.go
+++ b/internal/statsengine/snapshot.go
@@ -237,28 +237,6 @@ func (s Snapshot) FamiliesCount() int {
 	return len(s.families)
 }
 
-// NonIOFamilies returns family rows outside the file-system/fd-focused family.
-func (s Snapshot) NonIOFamilies() []FamilySnapshot {
-	rows := make([]FamilySnapshot, 0, len(s.families))
-	for _, row := range s.families {
-		if types.IsNonIOSyscallFamily(row.Family) {
-			rows = append(rows, row)
-		}
-	}
-	return rows
-}
-
-// NonIOFamiliesCount returns number of non-FS syscall-family rows.
-func (s Snapshot) NonIOFamiliesCount() int {
-	count := 0
-	for _, row := range s.families {
-		if types.IsNonIOSyscallFamily(row.Family) {
-			count++
-		}
-	}
-	return count
-}
-
 // TopNSyscalls returns at most n per-syscall rows in ranking order.
 // Callers must treat returned data as read-only.
 func (s Snapshot) TopNSyscalls(n int) []SyscallSnapshot {
diff --git a/internal/statsengine/snapshot_test.go b/internal/statsengine/snapshot_test.go
index 9b54409..d5cb7aa 100644
--- a/internal/statsengine/snapshot_test.go
+++ b/internal/statsengine/snapshot_test.go
@@ -124,35 +124,6 @@ func TestNilAccessorsRemainNil(t *testing.T) {
 	}
 }
 
-func TestSnapshotNonIOFamilies(t *testing.T) {
-	s := NewSnapshotWithFamilies(
-		nil,
-		nil,
-		nil,
-		nil,
-		[]FamilySnapshot{
-			{Family: types.FamilyFS, Name: "FS"},
-			{Family: types.FamilyPolling, Name: "Polling"},
-			{Family: types.FamilyProcess, Name: "Process"},
-		},
-		nil,
-		nil,
-		HistogramSnapshot{},
-		HistogramSnapshot{},
-	)
-
-	rows := s.NonIOFamilies()
-	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 := s.NonIOFamiliesCount(); got != 2 {
-		t.Fatalf("NonIOFamiliesCount = %d, want 2", got)
-	}
-}
-
 func TestTopNAccessors(t *testing.T) {
 	s := NewSnapshot(
 		nil,