UserSchedule entity — personal availability grid for matching

[SanAlexis]

Context

Each user provides their availability at onboarding for future compatibility matching in the Lookup Layer.

Data model

create table if not exists public.user_schedules (
  user_id uuid primary key references public.users (id) on delete cascade,
  timezone text not null,
  availability_grid jsonb not null default '{}'::jsonb
  -- day × hour bitmask, e.g. {"mon": [9,10,11,14,15], "tue": [9,10], ...}
);

Acceptance criteria

• DB migration creates user_schedules table
• Onboarding flow collects timezone + weekly availability grid
• Grid input: day × hour selector (visual grid UI)
• Data used later for schedule overlap matching in Lookup Layer (Milestone 7)