From 0e0c709f478340ec737cbc8db3aa8f1e4729db7b Mon Sep 17 00:00:00 2001
From: Rich Haase <46830998+richhaase@users.noreply.github.com>
Date: Mon, 9 Mar 2026 08:37:06 -0600
Subject: [PATCH] fix: DST boundary bug in weekly workout grouping

When DST springs forward (e.g. March 8 in America/Denver), the
millisecond difference between consecutive Monday midnights is ~6.96
days instead of 7.0, causing Math.floor to assign workouts to the
previous week. Fix by rounding to nearest day before dividing by 7.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 src/stats.ts | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/stats.ts b/src/stats.ts
index fdb768f..1b75bed 100644
--- a/src/stats.ts
+++ b/src/stats.ts
@@ -79,9 +79,10 @@ export function buildWeekSummaries(
     if (t < cutoff || t > now) continue;
 
     const monday = mondayOf(t);
-    const idx = Math.floor(
-      (monday.getTime() - cutoff.getTime()) / (1000 * 60 * 60 * 24 * 7),
+    const diffDays = Math.round(
+      (monday.getTime() - cutoff.getTime()) / (1000 * 60 * 60 * 24),
     );
+    const idx = Math.floor(diffDays / 7);
     if (idx < 0 || idx >= weeks) continue;
 
     const ws = summaries[idx]!;