feat(board): let the boards use a laptop's width above the phone cap

[Jammy2211]

Reported against the Heart board from a laptop: the page reads as a long column of text. The cap that causes it is a family contract, so it is fixed here rather than in one board.

The problem

body{max-width:44rem} is a phone reading measure. Above the cap it stops being a measure and starts being a waste: the data boards — Heart's check table with a detail list under most rows, Mind's task lists — run ~40 short lines down a 704px strip with the rest of a laptop's screen left empty.

The fix

One media query, next to the body rule:

@media(min-width:64rem){body{max-width:60rem}}

Applied only above the existing cap. Every narrower viewport — phone, tablet, split-screen — keeps the current shape byte for byte, so the reading measure stays where it was designed to matter. All five boards inherit it, since they all render through this sheet.

Verification

• pytest tests → 606 passed (tests/test_board_theme.py + tests/test_board.py green on their own too).
• Re-rendered the Heart board from its published board.json against the patched theme: CSS-only diff, no markup change on any surface.

Companion: PyAutoLabs/PyAutoHeart#191 fixes the other half of the same report (the board's detail lines losing their column alignment) — independent, either can merge first.

🤖 Generated with Claude Code

https://claude.ai/code/session_018q6ZrgG6u8o8ENYZ7cq3Lr