Redesign layout: 3-per-row 2-row grid, 6 days, bigger fonts

- Show 6 days in a 3x2 grid (3 columns, 2 rows) with info panel
  spanning the full right column
- Day columns explicitly grid-placed to prevent auto-flow into panel column
- Larger fonts throughout: event cards 14px, day number 26px, clock 52px

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app.py

@@ -133,7 +133,7 @@ def parse_member_and_title(summary, family_members):
     return None, summary
 
 
-NUM_DAYS = 5
+NUM_DAYS = 6
 
 
 def empty_days_payload(start_date, members):