[salmun-nister]

Fixes #11

1. Stitch the two day files

Model.js gains a pure helper (testable outside QML):

// Trailing 24 h of per-minute typical downlink, oldest -> newest, as a fixed
// 1440-slot window: yesterday's minutes (cur+1 ... 1439) then today's (0 ... cur).
// A day file stores {} for minutes with no data, which maps to a null gap.
function rolling24h(prevMinutes, todayMinutes, curMinute) { ... }

Panel.qml reads day-<yesterday>.json alongside today's (same dish partition), with prevDayStamp recomputed on the existing 2 s refresh, so the rollover needs no restart. stampOffset() steps the local date with Date.setDate rather than subtracting 24 h, which survives DST.

Path hygiene while wiring the second file: dayDir/dayBase stay empty until the dish identity arrives, so FileView does not probe a root-level day file that never exists, and both day FileViews set printErrors: false - yesterday's file legitimately does not exist on a fresh install and the reload would otherwise log a warning every 2 s.

2. Window summary instead of the duplicated live value

// Model.js - mean of the non-null entries; null when there is no data
function mean(values) { ... }

-              title: "TODAY"
-              valueText: ... s.live.typicalDownMbps ... "peak " + Model.fmtMbps(root.dayPeak) ...
+              title: "LAST 24H"
+              valueText: {
+                var parts = []
+                if (root.dayAvg !== null) parts.push("avg " + Model.fmtMbps(root.dayAvg))
+                if (root.dayPeak !== null) parts.push("peak " + Model.fmtMbps(root.dayPeak))
+                return parts.length ? parts.join(" · ") : "—"
+              }

Side effect worth noting: the line no longer collapses to a single label when the link goes idle, because window statistics exist even with no current samples.

Testing

• window length is always 1440; index mapping matches the source files with zero mismatches;
• at cur = 0, the window equals yesterday's 1 ... 1439 plus today's 0;
• no previous file -> 1440 slots, only today populated; no files -> all null, renders —;
• mean(): [1,2,3] -> 2, [1,null,3] -> 2, [] -> null, null -> null;
• visual: a synthetic full-day file fills the band edge to edge; the real day file reproduces the expected right-hand band.

Known limitation

DST days (23 h / 25 h) shift the window by an hour twice a year; minute-of-day arithmetic is used deliberately instead of epoch math.

Scope

Display only. No Go changes, so backend/bin/starlinkd is untouched and the release gate's byte-identical check is unaffected. Independent of the other open PRs.