refactor(tui): remove full-page detail, SLA, and history views

All monitor detail content now lives in the sidebar panel.
Delete the full-page viewDetailPanel, viewSLAPanel, viewHistoryPanel,
handleDetailKey, handleSLAKey, handleHistoryKey, openSLAView, and
related dead code (histogram, sparkline tooltip, detailViewport).

Remove stateDetail, stateSLA, stateHistory session states.
Update tests to use detailOpen/detailMode instead of removed states.

internal/tui/view_sla.go

@@ -5,8 +5,6 @@ import (
 	"math"
 	"strings"
 	"time"
-
-	"github.com/charmbracelet/lipgloss"
 )
 
 var slaPeriods = []struct {
@@ -21,91 +19,6 @@ var slaPeriods = []struct {
 	{"90d", "4", 90 * 24 * time.Hour, 90},
 }
 
-func (m Model) viewSLAPanel() string {
-	var b strings.Builder
-
-	header := "  " + m.st.subtleStyle.Render("SLA >") + " " + m.st.titleStyle.Render(m.slaSiteName)
-	b.WriteString(header + "\n")
-	b.WriteString(m.divider() + "\n")
-
-	period := slaPeriods[m.slaPeriodIdx]
-	b.WriteString("  " + m.st.subtleStyle.Render("Period: Last "+period.label) + "\n\n")
-
-	r := m.slaReport
-
-	barWidth := m.dividerWidth() - 30
-	if barWidth < 10 {
-		barWidth = 10
-	}
-	bar := m.uptimeBar(r.UptimePct, barWidth)
-	uptimeColor := m.st.specialStyle
-	if r.UptimePct < uptimeExcellentPct {
-		uptimeColor = m.st.warnStyle
-	}
-	if r.UptimePct < uptimeGoodPct {
-		uptimeColor = m.st.dangerStyle
-	}
-	fmt.Fprintf(&b, "  %-16s %s  %s\n", m.st.subtleStyle.Render("Uptime"), uptimeColor.Render(fmt.Sprintf("%s%%", fmtPct(r.UptimePct))), bar)
-	fmt.Fprintf(&b, "  %-16s %s\n", m.st.subtleStyle.Render("Downtime"), fmtDuration(r.Downtime))
-	fmt.Fprintf(&b, "  %-16s %d\n", m.st.subtleStyle.Render("Outages"), r.OutageCount)
-
-	if r.OutageCount > 0 {
-		fmt.Fprintf(&b, "  %-16s %s\n", m.st.subtleStyle.Render("Longest"), fmtDuration(r.LongestOut))
-		fmt.Fprintf(&b, "  %-16s %s\n", m.st.subtleStyle.Render("MTTR"), fmtDuration(r.MTTR))
-		fmt.Fprintf(&b, "  %-16s %s\n", m.st.subtleStyle.Render("MTBF"), fmtDuration(r.MTBF))
-	}
-
-	b.WriteString("\n" + m.divider() + "\n")
-
-	if len(m.slaDailyBreakdown) > 0 {
-		b.WriteString(m.slaViewport.View())
-	}
-
-	b.WriteString("\n" + m.divider() + "\n")
-
-	var keys []string
-	for i, p := range slaPeriods {
-		label := fmt.Sprintf("[%s] %s", p.key, p.label)
-		if i == m.slaPeriodIdx {
-			keys = append(keys, m.st.titleStyle.Render(label))
-		} else {
-			keys = append(keys, m.st.subtleStyle.Render(label))
-		}
-	}
-	b.WriteString("  " + strings.Join(keys, "  "))
-	b.WriteString("  " + m.st.subtleStyle.Render("[↑/↓] Scroll  [q/Esc] Back"))
-
-	return lipgloss.NewStyle().Padding(1, 2).Render(b.String())
-}
-
-func (m Model) buildSLADailyContent() string {
-	var b strings.Builder
-
-	barWidth := m.dividerWidth() - 30
-	if barWidth < 10 {
-		barWidth = 10
-	}
-
-	b.WriteString("  " + m.st.titleStyle.Render("DAILY BREAKDOWN") + "\n")
-	for _, day := range m.slaDailyBreakdown {
-		dateStr := day.Date.Format("Jan 02")
-		bar := m.uptimeBar(day.UptimePct, barWidth)
-		pctStr := fmtPct(day.UptimePct) + "%"
-
-		color := m.st.specialStyle
-		if day.UptimePct < uptimeExcellentPct {
-			color = m.st.warnStyle
-		}
-		if day.UptimePct < uptimeGoodPct {
-			color = m.st.dangerStyle
-		}
-
-		fmt.Fprintf(&b, "  %-8s %s  %s\n", m.st.subtleStyle.Render(dateStr), bar, color.Render(pctStr))
-	}
-
-	return b.String()
-}
-
 func (m Model) uptimeBar(pct float64, width int) string {
 	filled := int(math.Round(pct / 100 * float64(width)))
 	if filled > width {