- groupEvents: buildMonthGrid covers the entire current calendar month
padded to full weeks; adjacent-month padding days are flagged (dimmed)
but can still hold events; events outside the window are counted
- Localised short weekday names as column headers; month/year label
- Webview renders a CSS grid: day cells with date number, today border
highlight, clickable event chips (colour, icon/glyph, strikethrough,
ellipsis overflow)
- Config accepts view: month-grid (alias: grid)
- SPEC.md updated; 5 new tests (47 total)
