Scale up energy flow diagram on mobile

[eetu]

Summary

• Bump node circle radius (36 → 42), stroke width (2 → 4), node title font (18 → 24), subtitle (16 → 20), and flow line stroke (3 → 5) on screens ≤ 600px.
• Tighten viewBox on mobile (80 20 640 425) so unused margins don't waste space.
• Trim card padding 1.5em → 1em on mobile for Flow / Summary / DailyHistory.
• Drop status row from light group toggle.

Test plan

• Mobile (< 600px): flow nodes, lines, and labels visibly larger; no clipping at viewBox edges; values inside circles render at correct stroke weight.
• Desktop: layout unchanged.
• Light group toggle: name + bulb only, status row gone.