Both the single-run path and the campaign scheduler drove long-lived
asyncio tasks through their own duplicated _tasks/_cancel_events dicts and
shutdown loops. Collapse them into one deep TaskRegistry module,
instantiated as run_registry and campaign_registry. launch() creates the
cancel event before the task (so a cancel during startup is never lost),
wires done-callback cleanup, and is idempotent per id; this makes runs.py's
hard-cancel fallback provably dead, so it is removed. App shutdown now
gracefully stops in-flight runs too, not just campaigns.
Add a thin async loop (run_campaign_loop) that ticks on real wall-clock time,
maps elapsed×time_scale to a window offset via the pure decide_schedule, spawns
due child Runs, and marks the campaign COMPLETED at window end. All authority
lives in the DB (started_at, spawned_indices, status), so the app lifespan can
resume every RUNNING campaign on startup without double-spawning and stop all
loops gracefully on shutdown. A failing plan entry is skipped and recorded
rather than wedging the campaign.
Creating a campaign now starts its loop; POST /api/campaigns/{id}/cancel stops
further spawning (completed child Runs are kept); GET /api/campaigns/{id}
reports live progress (window offset, spawned/completed Run counts).
