_agent_api_headers sent the UNSIGNED sentinel when ROBOCO_AGENT_AUTH_SECRET
was unset, but the dev-mode middleware rejects a presented-but-unverifiable
token with 401 signature mismatch (while accepting a missing one). The
cell-PM auto-submit self-call 401'd in every dev run, regressing
test_auto_submit_cuts_the_pm_turn. Attach the token only when a secret is
set. Also fix the FromClause.update mypy error in the per-project
video-engine opt-out test (ORM row load + flush).
Renn F
2e938d20d6