Stage 0's "returns and reads in >=2 weeks" gate can't be met while discovery
is host-side manual (`tapir run`): a newly onboarded user sees an empty list
and never comes back. Make Tapir watch on its own.
cmdServe launches a background goroutine (when TAPIR_DISCOVERY_INTERVAL > 0)
that runs a discovery pass for ALL users on that cadence: enumerate via the
un-RLS'd ListAllUsers, then run each user's pass through the EXISTING
runner.Runner — the only new code is the per-user loop, not a new scheduler.
Run-once-on-startup then ticked; ctx-cancelled on SIGTERM; per-user failures
(including buildUserRunner errors) are logged and skipped so one bad user
never aborts the rest. interval <= 0 disables it entirely (dev/tests).
buildUserRunner binds each runner to that user's own YouTube refresh token
(web.YouTubeTokenRef) — the Stage-1 per-tenant ref — reusing buildProcessor's
engine wiring. SetFetchRate is also wired in cmdServe so the click-path shares
the gate.
SINGLE-REPLICA is now load-bearing: the loop lives in the web process, so >1
replica double-runs discovery (429s + duplicate work). Documented in cmdServe
and warned at startup.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>