Working calendar — weekends + holidays

Each project has a working calendar that says which days don't count as work — weekends, public holidays, planned shutdowns. CPM, leveling, cascade, and Monte Carlo all skip these days when measuring durations.

Editing the calendar:
1. Open a project's Overview tab
2. Click **Working calendar**
3. Toggle off-days (default: Sat + Sun)
4. Add specific date holidays via the date picker

What changes:
• Durations are measured in *working* days (a Mon–Fri task = 5 days)
• Cascade snaps dependents to the next working day on drop
• Monte Carlo samples in working days
• Existing task dates aren't shifted — only how durations are *measured* changes

If your team has a 4-day week, a 6-day construction schedule, or recurring vendor blackouts, configure them here once and the math respects them everywhere.