requireDaemonTaskAccess used to turn any GetAgentTask error into
404 "task not found", including transient DB connection / pool errors.
Combined with PR #2107 — which added 404+"task not found" as a daemon
cancellation trigger — that means a single DB hiccup could kill an
in-flight agent run.
Distinguish pgx.ErrNoRows (real "task gone", 404) from other errors
(transient, 500 + warn log) using the existing isNotFound helper.
Tests cover both paths via the mockDB pattern already used by
TestFindOrCreateUserGating.
Co-authored-by: multica-agent <github@multica.ai>