v0.5.1 — /issues two-milestone horizon pacing

Added

• /issues two-milestone horizon — on a roadmap-index input, /issues now proposes filing only the current phase + the next phase (not the entire roadmap), names the phases it's skipping, and asks before filing more. Rolling forward is idempotent: re-running advances the window once phases complete.

This is the team practice that translates cleanly to solo work — it gives team discipline (issue-per-PR, milestone-scoped) without team overhead (stale labels, multi-quarter backlogs, triage meetings).

Changed

• /issues "After writing" guidance now reinforces the horizon: when the current phase is roughly halfway done, re-run to file the next-next phase.

See CHANGELOG.md.