extract TUI Model god class into focused sub-controllers

Split the 1389-line tui.go Model into three focused sub-controllers
that each own a single concern:

- filterstack.go (filterStack): owns the filter chain, undo history,
  and label stack; provides push/pop/rebindProcessFilters API so the
  Model never manipulates filter slices directly.

- tracelifecycle.go (traceLifecycle): owns trace start/stop and the
  active context.CancelFunc; provides beginCmd/stop API; also houses
  the recorder helpers (recorderStart/Stop/Active/Status) and the
  auto-reset cycle logic (nextAutoResetInterval, autoResetCycle).

- screenrouter.go (screenRouter): owns the picker-return bookmark
  (pickerReturn) and the applyWindowSizeToPicker helper so screen
  transition code in tui.go delegates to it.

The Model.Update switch is split into dispatchTypedMsg (framework
messages) and dispatchAppMsg (app messages) to keep each helper
under the 50-line limit. View is split into viewPickerScreen and
viewDashboardScreen for the same reason.

All functions are ≤50 lines. go test ./internal/tui/... passes.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 34 insertions, 34 deletions

diff --git a/internal/tui/tui_test.go b/internal/tui/tui_test.go
index b8d6108..f0d4c2f 100644
--- a/internal/tui/tui_test.go
+++ b/internal/tui/tui_test.go
@@ -226,7 +226,7 @@ func TestQuitInvokesTraceStop(t *testing.T) {
 	m.screen = ScreenDashboard
 	m.attaching = false
 	done := make(chan struct{})
-	m.traceStop = func() {
+	m.tracer.traceStop = func() {
 		close(done)
 	}
 
@@ -291,7 +291,7 @@ func TestQuitKeyOnReselectPIDPickerReturnsToDashboardLikeEsc(t *testing.T) {
 	if updated.quitting {
 		t.Fatalf("expected q in reselect picker to behave like esc, not quit")
 	}
-	if updated.proc.pickerReturn != nil {
+	if updated.router.pickerReturn != nil {
 		t.Fatalf("expected picker return context to clear after cancel")
 	}
 	if updated.proc.pid != 1111 || updated.proc.tid != 2222 {
@@ -332,7 +332,7 @@ func TestEscOnReselectPIDPickerReturnsToDashboard(t *testing.T) {
 	if updated.quitting {
 		t.Fatalf("expected esc in reselect picker not to quit app")
 	}
-	if updated.proc.pickerReturn != nil {
+	if updated.router.pickerReturn != nil {
 		t.Fatalf("expected picker return context to clear after cancel")
 	}
 	if updated.proc.pid != 3333 || updated.proc.tid != 4444 {
@@ -1073,7 +1073,7 @@ func TestSelectPIDKeyReturnsToFreshPickerAndStopsTrace(t *testing.T) {
 	m.width = 120
 	m.height = 30
 	stopped := false
-	m.traceStop = func() { stopped = true }
+	m.tracer.traceStop = func() { stopped = true }
 
 	next, _ := m.Update(tea.KeyPressMsg{Code: []rune{'2'}[0], Text: string([]rune{'2'})})
 	m = next.(Model)
@@ -1090,7 +1090,7 @@ func TestSelectPIDKeyReturnsToFreshPickerAndStopsTrace(t *testing.T) {
 	if updated.attaching {
 		t.Fatalf("expected attaching=false on picker screen")
 	}
-	if updated.traceStop != nil {
+	if updated.tracer.traceStop != nil {
 		t.Fatalf("expected traceStop to be cleared after stopping")
 	}
 	if cmd == nil {
@@ -1118,7 +1118,7 @@ func TestSelectTIDKeyReturnsToPickerWhenPIDFilterIsAll(t *testing.T) {
 	m.height = 30
 
 	stopped := false
-	m.traceStop = func() { stopped = true }
+	m.tracer.traceStop = func() { stopped = true }
 
 	next, _ := m.Update(tea.KeyPressMsg{Code: []rune{'2'}[0], Text: string([]rune{'2'})})
 	m = next.(Model)
@@ -1146,7 +1146,7 @@ func TestSelectTIDKeyReturnsToPickerWhenSinglePIDSelected(t *testing.T) {
 	m.height = 30
 
 	stopped := false
-	m.traceStop = func() { stopped = true }
+	m.tracer.traceStop = func() { stopped = true }
 
 	next, _ := m.Update(tea.KeyPressMsg{Code: []rune{'2'}[0], Text: string([]rune{'2'})})
 	m = next.(Model)
@@ -1245,8 +1245,8 @@ func TestStreamFilterModalConsumesEKeyInsteadOfOpeningExport(t *testing.T) {
 	if m.exporter.Visible() {
 		t.Fatalf("expected export modal to remain closed while stream filter modal handles typing")
 	}
-	if m.filter.global.Syscall == nil || m.filter.global.Syscall.Pattern != "ope" {
-		t.Fatalf("expected typed syscall filter to be stored globally, got %+v", m.filter.global.Syscall)
+	if m.filters.global.Syscall == nil || m.filters.global.Syscall.Pattern != "ope" {
+		t.Fatalf("expected typed syscall filter to be stored globally, got %+v", m.filters.global.Syscall)
 	}
 }
 
@@ -1416,7 +1416,7 @@ func TestGlobalFilterModalOpensFromDashboardShortcut(t *testing.T) {
 func TestQuitClosesGlobalFilterModalWithoutQuitting(t *testing.T) {
 	m := NewModel(-1, func(context.Context) error { return nil })
 	m.screen = ScreenDashboard
-	m.filterModal = m.filterModal.Open(m.filter.global)
+	m.filterModal = m.filterModal.Open(m.filters.global)
 
 	next, cmd := m.Update(tea.KeyPressMsg{Code: []rune{'q'}[0], Text: string([]rune{'q'})})
 	m = next.(Model)
@@ -1437,7 +1437,7 @@ func TestGlobalFilterModalUpdatesStoredFilterState(t *testing.T) {
 	m.attaching = false
 
 	stopped := false
-	m.traceStop = func() { stopped = true }
+	m.tracer.traceStop = func() { stopped = true }
 
 	next, _ := m.Update(tea.KeyPressMsg{Code: []rune{'f'}[0], Text: string([]rune{'f'})})
 	m = next.(Model)
@@ -1455,8 +1455,8 @@ func TestGlobalFilterModalUpdatesStoredFilterState(t *testing.T) {
 	if m.filterModal.Visible() {
 		t.Fatalf("expected global filter modal to close after esc")
 	}
-	if m.filter.global.Syscall == nil || m.filter.global.Syscall.Pattern != "read" {
-		t.Fatalf("expected stored global filter updated from modal, got %+v", m.filter.global.Syscall)
+	if m.filters.global.Syscall == nil || m.filters.global.Syscall.Pattern != "read" {
+		t.Fatalf("expected stored global filter updated from modal, got %+v", m.filters.global.Syscall)
 	}
 	if !stopped {
 		t.Fatalf("expected filter apply to stop the active trace")
@@ -1472,7 +1472,7 @@ func TestGlobalFilterCloseWithoutChangesDoesNotRestartTrace(t *testing.T) {
 	m.attaching = false
 
 	stopped := false
-	m.traceStop = func() { stopped = true }
+	m.tracer.traceStop = func() { stopped = true }
 
 	next, _ := m.Update(tea.KeyPressMsg{Code: []rune{'f'}[0], Text: string([]rune{'f'})})
 	m = next.(Model)
@@ -1502,7 +1502,7 @@ func TestPausedStreamEnterAppliesSelectedCellAsGlobalFilter(t *testing.T) {
 	m.height = 30
 
 	stopped := false
-	m.traceStop = func() { stopped = true }
+	m.tracer.traceStop = func() { stopped = true }
 
 	rb := eventstream.NewRingBuffer()
 	rb.Push(eventstream.StreamEvent{
@@ -1540,8 +1540,8 @@ func TestPausedStreamEnterAppliesSelectedCellAsGlobalFilter(t *testing.T) {
 	if cmd == nil {
 		t.Fatalf("expected applying selected-cell global filter to restart tracing")
 	}
-	if m.filter.global.Comm == nil || m.filter.global.Comm.Pattern != "systemd" {
-		t.Fatalf("expected selected comm applied globally, got %+v", m.filter.global.Comm)
+	if m.filters.global.Comm == nil || m.filters.global.Comm.Pattern != "systemd" {
+		t.Fatalf("expected selected comm applied globally, got %+v", m.filters.global.Comm)
 	}
 	if !stopped {
 		t.Fatalf("expected selected-cell global filter to stop the active trace")
@@ -1549,8 +1549,8 @@ func TestPausedStreamEnterAppliesSelectedCellAsGlobalFilter(t *testing.T) {
 	if !m.attaching {
 		t.Fatalf("expected selected-cell global filter to restart tracing")
 	}
-	if len(m.filter.stack) != 1 || m.filter.stack[0] != "comm~systemd" {
-		t.Fatalf("expected selected-cell action pushed to filter stack, got %+v", m.filter.stack)
+	if len(m.filters.stack) != 1 || m.filters.stack[0] != "comm~systemd" {
+		t.Fatalf("expected selected-cell action pushed to filter stack, got %+v", m.filters.stack)
 	}
 }
 
@@ -1570,18 +1570,18 @@ func TestGlobalFilterUndoKeyPopsLatestStackEntry(t *testing.T) {
 
 	m.attaching = false
 	stopped := false
-	m.traceStop = func() { stopped = true }
+	m.tracer.traceStop = func() { stopped = true }
 
 	next, cmd := m.Update(tea.KeyPressMsg{Code: []rune{'F'}[0], Text: string([]rune{'F'})})
 	m = next.(Model)
 	if cmd == nil {
 		t.Fatalf("expected F to trigger global filter undo")
 	}
-	if m.filter.global.IsActive() {
-		t.Fatalf("expected undo to restore the previous all-filter state, got %+v", m.filter.global)
+	if m.filters.global.IsActive() {
+		t.Fatalf("expected undo to restore the previous all-filter state, got %+v", m.filters.global)
 	}
-	if len(m.filter.stack) != 0 || len(m.filter.history) != 0 {
-		t.Fatalf("expected filter stack/history cleared after undo, got stack=%+v history=%d", m.filter.stack, len(m.filter.history))
+	if len(m.filters.stack) != 0 || len(m.filters.history) != 0 {
+		t.Fatalf("expected filter stack/history cleared after undo, got stack=%+v history=%d", m.filters.stack, len(m.filters.history))
 	}
 	if !stopped {
 		t.Fatalf("expected undo to stop the active trace")
@@ -1612,7 +1612,7 @@ func TestPausedStreamEscUndoesLatestGlobalFilter(t *testing.T) {
 	m.dashboard.SetStreamSource(rb)
 	m.attaching = false
 	stopped := false
-	m.traceStop = func() { stopped = true }
+	m.tracer.traceStop = func() { stopped = true }
 
 	next, _ = m.Update(tea.WindowSizeMsg{Width: 120, Height: 30})
 	m = next.(Model)
@@ -1631,11 +1631,11 @@ func TestPausedStreamEscUndoesLatestGlobalFilter(t *testing.T) {
 	if cmd == nil {
 		t.Fatalf("expected esc undo to restart tracing")
 	}
-	if m.filter.global.IsActive() {
-		t.Fatalf("expected esc undo to restore all-filter state, got %+v", m.filter.global)
+	if m.filters.global.IsActive() {
+		t.Fatalf("expected esc undo to restore all-filter state, got %+v", m.filters.global)
 	}
-	if len(m.filter.stack) != 0 {
-		t.Fatalf("expected filter stack cleared after esc undo, got %+v", m.filter.stack)
+	if len(m.filters.stack) != 0 {
+		t.Fatalf("expected filter stack cleared after esc undo, got %+v", m.filters.stack)
 	}
 	if !stopped {
 		t.Fatalf("expected esc undo to stop the active trace")
@@ -1681,7 +1681,7 @@ func TestProcessesTabEnterAppliesSelectedProcessAsGlobalFilter(t *testing.T) {
 	m.height = 30
 
 	stopped := false
-	m.traceStop = func() { stopped = true }
+	m.tracer.traceStop = func() { stopped = true }
 
 	snap := statsengine.NewSnapshot(nil, nil, nil, nil, nil, []statsengine.ProcessSnapshot{
 		{PID: 111, Comm: "alpha", Syscalls: 9},
@@ -1706,11 +1706,11 @@ func TestProcessesTabEnterAppliesSelectedProcessAsGlobalFilter(t *testing.T) {
 	if cmd == nil {
 		t.Fatalf("expected selected process filter to restart tracing")
 	}
-	if m.filter.global.PID == nil || m.filter.global.PID.Value != 222 {
-		t.Fatalf("expected selected process pid applied globally, got %+v", m.filter.global.PID)
+	if m.filters.global.PID == nil || m.filters.global.PID.Value != 222 {
+		t.Fatalf("expected selected process pid applied globally, got %+v", m.filters.global.PID)
 	}
-	if len(m.filter.stack) != 1 || m.filter.stack[0] != "pid=222" {
-		t.Fatalf("expected pid filter pushed to stack, got %+v", m.filter.stack)
+	if len(m.filters.stack) != 1 || m.filters.stack[0] != "pid=222" {
+		t.Fatalf("expected pid filter pushed to stack, got %+v", m.filters.stack)
 	}
 	if !stopped {
 		t.Fatalf("expected selected process filter to stop the active trace")