The ALLOW_DEV_TEST_ENDPOINTS short-circuit on create wrote
'dev-stub-<ms>' as the channel ID. boardChannelUpdateSchema requires
^[A-Z0-9]+$, so the very next edit on the same channel hit a 400 from
Zod and the table never updated. Use base36-uppercased timestamp with
a 'CDEV' prefix so the stub survives a round-trip through the patch
route. Live path is unchanged.
Mirrors the dev-mode short-circuit in invite.post.js. Without
SLACK_BOT_TOKEN, board-channel create returned 500 'Slack integration
not configured', breaking e2e in CI. With ALLOW_DEV_TEST_ENDPOINTS=true,
generate a stub channel ID and proceed; everything DB-side still runs.
