feat(tui): 30-day uptime timeline in inline detail panel

Statuspage-style colored bar — one █ per day, colored by uptime:
green (>= 99%), yellow (>= 95%), red (< 95%), gray (no data).
30-day percentage shown to the right.

Daily breakdown computed via ComputeDailyBreakdown from state_changes
and loaded alongside detail data in loadDetailCmd. Auto-updates on
cursor move.

internal/tui/uptime_timeline.go

@@ -0,0 +1,50 @@
+package tui
+
+import (
+	"fmt"
+	"strings"
+
+	"gitea.lerkolabs.com/lerkolabs/uptop/internal/monitor"
+)
+
+func (m Model) uptimeTimeline(days []monitor.DayReport, width int) string {
+	if len(days) == 0 {
+		return m.st.subtleStyle.Render("No uptime data")
+	}
+
+	maxDays := width - 10
+	if maxDays < 10 {
+		maxDays = 10
+	}
+
+	display := days
+	if len(display) > maxDays {
+		display = display[len(display)-maxDays:]
+	}
+
+	var sb strings.Builder
+	for _, d := range display {
+		ch := "█"
+		switch {
+		case d.UptimePct >= 99.0:
+			sb.WriteString(m.st.specialStyle.Render(ch))
+		case d.UptimePct >= 95.0:
+			sb.WriteString(m.st.warnStyle.Render(ch))
+		case d.UptimePct > 0:
+			sb.WriteString(m.st.dangerStyle.Render(ch))
+		default:
+			sb.WriteString(m.st.subtleStyle.Render("░"))
+		}
+	}
+
+	pct := days[len(days)-1].UptimePct
+	pctStyle := m.st.specialStyle
+	if pct < 99.0 {
+		pctStyle = m.st.dangerStyle
+	} else if pct < 99.9 {
+		pctStyle = m.st.warnStyle
+	}
+	sb.WriteString("  " + pctStyle.Render(fmt.Sprintf("%.2f%%", pct)))
+
+	return sb.String()
+}