v2.10.0

v2.10.0

What changed

• observability: answer who-uses-it, how long they wait, and where sync time goes
• attendance: stop painting the stale Absences card during a scope sync

Internal

• screenshot of the attendance tab mid-sync (old card absent)
• pin the analytics arithmetic, visit span, and item beacon
• observability: filter 5xx panels on status_class, and gate invented labels
• rewrite the new panels in plain language
• observability: shorten two truncated titles, finish the plain-legend rename
• move visit tracking out of app.py into observability