fix: address review findings for prefetch and column width

- Short-circuit countVisibleJobsAfter once threshold reached (perf)
- Extract maybePrefetch helper to deduplicate prefetch logic
- Clamp flex columns to 1 char when no remaining space (narrow terms)
- Add clarifying comment about spacing dual accounting in colWidths

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

Author: mariusvniekerk

cmd/roborev/tui/handlers.go

@@ -308,10 +308,8 @@ func (m model) handleDownKey() (tea.Model, tea.Cmd) {
 		if nextIdx >= 0 {
 			m.selectedIdx = nextIdx
 			m.updateSelectedJobID()
-			// Prefetch more jobs when approaching the end of loaded data
-			if m.canPaginate() && m.countVisibleJobsAfter(nextIdx) < queuePrefetchBuffer {
-				m.loadingMore = true
-				return m, m.fetchMoreJobs()
+			if cmd := m.maybePrefetch(nextIdx); cmd != nil {
+				return m, cmd
 			}
 		} else if m.canPaginate() {
 			m.loadingMore = true
@@ -344,10 +342,8 @@ func (m model) handleNextKey() (tea.Model, tea.Cmd) {
 		if nextIdx >= 0 {
 			m.selectedIdx = nextIdx
 			m.updateSelectedJobID()
-			// Prefetch more jobs when approaching the end of loaded data
-			if m.canPaginate() && m.countVisibleJobsAfter(nextIdx) < queuePrefetchBuffer {
-				m.loadingMore = true
-				return m, m.fetchMoreJobs()
+			if cmd := m.maybePrefetch(nextIdx); cmd != nil {
+				return m, cmd
 			}
 		} else if m.canPaginate() {
 			m.loadingMore = true

cmd/roborev/tui/nav.go

@@ -1,6 +1,9 @@
 package tui
 
-import "github.com/roborev-dev/roborev/internal/storage"
+import (
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/roborev-dev/roborev/internal/storage"
+)
 
 // updateSelectedJobID updates the tracked job ID after navigation
 func (m *model) updateSelectedJobID() {
@@ -192,17 +195,32 @@ func (m model) findPrevVisibleJob(currentIdx int) int {
 	return -1
 }
 
-// countVisibleJobsAfter returns how many visible jobs exist after currentIdx.
+// countVisibleJobsAfter returns the number of visible jobs after currentIdx,
+// short-circuiting once the count reaches queuePrefetchBuffer since callers
+// only need to know whether the count is below that threshold.
 func (m model) countVisibleJobsAfter(currentIdx int) int {
 	count := 0
 	for i := currentIdx + 1; i < len(m.jobs); i++ {
 		if m.isJobVisible(m.jobs[i]) {
 			count++
+			if count >= queuePrefetchBuffer {
+				return count
+			}
 		}
 	}
 	return count
 }
 
+// maybePrefetch triggers a page fetch if the cursor is near the end of loaded
+// data. Returns a tea.Cmd if a fetch was started, nil otherwise.
+func (m *model) maybePrefetch(idx int) tea.Cmd {
+	if m.canPaginate() && m.countVisibleJobsAfter(idx) < queuePrefetchBuffer {
+		m.loadingMore = true
+		return m.fetchMoreJobs()
+	}
+	return nil
+}
+
 // findFirstVisibleJob returns the index of the first visible job.
 func (m model) findFirstVisibleJob() int {
 	for i := range m.jobs {

cmd/roborev/tui/render_queue.go

@@ -322,7 +322,10 @@ func (m model) renderQueueView() string {
 		}
 
 		remaining := m.width - totalFixed
-		// Distribute remaining space among flex columns
+		// Distribute remaining space among flex columns.
+		// colWidths stores content-only width; StyleFunc adds spacing via
+		// s.Width(w + spacing(col, logicalCol)) so the total column width
+		// on screen = content width + inter-column spacing.
 		colWidths := make(map[int]int, len(visCols))
 		for c, fw := range fixedWidth {
 			colWidths[c] = fw
@@ -352,10 +355,11 @@ func (m model) renderQueueView() string {
 				}
 			}
 		} else if totalFlex > 0 {
-			// No remaining space: give flex columns minimal width
+			// No remaining space: give flex columns 1 char each to avoid
+			// overflow at very narrow terminal widths.
 			for _, c := range flexCols {
 				if !m.hiddenColumns[c] {
-					colWidths[c] = max(contentWidth[c], 1)
+					colWidths[c] = 1
 				}
 			}
 		}