HR

Split out of #137 (owner decision on D-02/attendance-to-payroll): overtime was deliberately kept out of PayrollService.ComputeLopDaysAsync scope ("a data gap should never silently cost an employee money" - half-day attendance and OT are harder rate-calculation problems than the LOP read that already shipped). Payroll itself is also still feature-flagged off (moduleFlags.payroll=false) with no timeline.

Needs a proper /brainstorming pass before any code, covering at minimum:

• Is overtime rate-based on attendance alone, or does it need shift-template/roster context (which shift, which rate multiplier)?
• Payroll run cadence: per-tenant or per-hospital (raised but not answered in #137)?
• What has to be true before the Payroll module flag can come off for a real tenant (data readiness, a rate-structure UI, statutory compliance fields, etc.)?

Not urgent - no tenant is asking for payroll processing yet. Parking this as its own ticket so #137 isn't blocked on it.