One file per feature from scope.md, named <scope id>-<slug>.md (for example F1.2-automatic-filter.md).
Written under the rules in clean-room.md. Implementation works from these files, not from the
reference material.
# F1.2 Automatic filter
Status: draft | reviewed | implemented
## User story
## Behavior (numbered, testable statements)
## Service surface (IEngineService methods/events added or used)
## APRS.NET dependencies (gap IDs, and any temporary SHIM)
## Desktop vs web differences
## Acceptance tests
## Open questions
## Sources (URL + access date, or "maintainer observation, YYYY-MM-DD"; "none: original design")