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/tui.go

@@ -199,6 +199,7 @@ type Model struct {
 	detailOpen          bool
 	detailChanges       []models.StateChange
 	detailChangesSiteID int
+	detailDailyDays     []monitor.DayReport
 
 	filterMode bool
 	filterText string