zapstore/spec/work/WORK-020-pow-progress.md

WORK-020 — PoW Difficulty and Progress

Feature: User-requested bootstrap proof-of-work feedback Status: Complete

Tasks

• 1. Increase bootstrap proof-of-work difficulty to 24 bits.
  • Files: lib/services/device_private_event_service.dart
• 2. Show elapsed mining time beneath the progress spinner.
  • Files: lib/services/device_state_service.dart, lib/screens/profile_screen.dart
• 3. Verify isolate mining and lifecycle behavior.
• 4. Self-review against INVARIANTS.md

Test Coverage

Scenario	Expected	Status
Bootstrap policy	Uses 24 proof-of-work bits	[x]
Bootstrap in progress	Spinner and elapsed time are visible	[x]
App backgrounded	Mining is not cancelled by the app lifecycle observer	[x]
Bootstrap failure	UI leaves the indefinite progress state	[x]

Decisions

2026-07-14 — Elapsed time source

Context: The mining executor does not expose progress callbacks to the UI. Decision: Store the bootstrap start time in the device-state status and derive elapsed time in the widget. This keeps mining isolated from presentation code.

Spec Issues

None

Progress Notes

2026-07-14: Reduced bootstrap difficulty to 24 bits, added elapsed mining feedback, and confirmed the focused service tests pass. Flutter analyze passes when run with a writable temporary HOME and the project package cache.