Add daily_schedule generator to find optimal maintenance windows
Introduces a new generator that analyzes journal activity patterns over
the past 7 days to identify the best time for scheduled maintenance tasks.
Uses a pre-hook to generate span summaries from segment data, replacing
the normal transcript clustering with structured activity window data.
- muse/daily_schedule.py: Pre-hook that scans segments and builds spans
- muse/daily_schedule.md: Prompt for JSON output with primary/fallback times
- think/models.py: Add TIER_LITE context for agent.daily_schedule.*
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>