Todoist-style: priorities P1-P4, estimates, FAB add form, Today view, natural quick add, drag-and-drop with haptics

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

server/schema.sql

@@ -23,6 +23,8 @@ create table if not exists tasks (
     waiting_for  text,           -- who/what is being waited on when status = 'waiting'
     due_date     date,
     defer_date   date,           -- hide from lists until this date
+    priority     int not null default 4 check (priority between 1 and 4),  -- 1=urgent … 4=low
+    estimate_min int check (estimate_min > 0),
     completed_at timestamptz,
     sort_order   double precision not null default 0,
     created_at   timestamptz not null default now(),