Update() routed form and confirm-delete states before handling
time.Time ticks, so those handlers swallowed the tick command and
permanently broke the refresh loop. After opening any form or
delete dialog, the TUI stopped auto-refreshing until restarted.
Move time.Time and WindowSizeMsg handling before state dispatch
so ticks always fire regardless of view state.
Also fix fmtRetries off-by-one: FailureCount=1 displayed as 0/N
instead of 1/N due to an erroneous subtract-one.
- Replace deprecated LineUp/LineDown/HalfViewUp/HalfViewDown with
ScrollUp/ScrollDown/HalfPageUp/HalfPageDown
- Use tagged switch for mouse button dispatch
- Use fmt.Fprintf instead of WriteString(Sprintf)
Full-screen scrollable history view accessible via [h] from detail
panel. Shows all state transitions with computed outage durations,
event density sparkline for flapping detection, and summary stats.
- Detail panel STATE CHANGES now shows outage duration per recovery
- Event density sparkline highlights flapping periods
- Summary footer: event count, outage count, avg outage duration
- Vim-style navigation (j/k/g/G) + mouse scroll in history view
tui.go (1032→164) and tab_sites.go (993→482) violated "small functions"
and "testable in isolation" standards. Extracted 6 new files by concern:
- format.go: pure formatting functions (fmtLatency, fmtUptime, etc.)
- sparkline.go: sparkline rendering (latency, heartbeat, group)
- update.go: Update method decomposed into 15 named handlers
- view_dashboard.go: View, dashboard composition, tab bar, footer
- view_detail.go: site detail panel
- data.go: data refresh with extracted sortSitesForDisplay/filterSites
Added 17 unit tests for the newly-testable pure functions covering
format, sparkline, sort ordering, and filter logic. No behavioral
changes — strict move-and-extract refactor.