UserBookingModal (reschedule): add lunch protection filtering, validation guard preventing invalid start>end unavailable blocks, composite each keys, and simplified available/unavailable rendering (lunch is invisible to users). BookingCreateModal (admin): add validation guard for unavailable blocks and fix composite each keys. Admin lunch protection behavior (30min min + amber warning) preserved. Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent) Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>