Production Synapse caps delayed events at 24h, but the dialog let any
later time be picked and then showed the raw server error. The date
input now has min/max (today .. now+24h), a too-late time shows "You can
schedule up to 24 hours ahead." as soon as it is picked (and blocks
Schedule), and ORG.MATRIX.MSC4140_DELAY_TOO_LARGE maps to the same text.
Fixes#275
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5